I received a default judgment (divorce) against my (ex) in Oct 09 (CA). She is now unhappy with the finances (she realized all that money I was giving her was taxable) and is talking about going to court to set it aside. I know that child custody is always available to be reopened. But...
What about spousal support? Retirement funds? Real estate?
I have not been collecting all that she is required to give me for child support - to help her out. ($400/mo)
What is my best strategy here?

It looks like I worded this poorly.
What does my ex have to do to reopen our case to reevaluate: support, retirement allocations and real estate? Is this costly?
What do I have to do to collect the full amount she is required to pay?

I received a default judgment (divorce) against my (ex) in Oct 09 (CA). She is now unhappy with the finances (she realized all that money I was giving her was taxable) and is talking about going to court to set it aside. I know that child custody is always available to be reopened. But ...
What about spousal support? Retirement funds? Real estate?
I have not been collecting all that she is required to give me for child support - to help her out. ($400/mo)
What is my best strategy here?

I don't quite understand the situation here when you say the money you gave her was a taxable item. The only item that you listed would have been the spousal support. That is taxable. Realestate may or may not be taxable depending on how it is treated.

As far as changing support level in either spousal or child support the courts normally don't want to see you again for about 2 years unless there has been a significant change in circumstance.

For collecting the full amount of a child support order the only thing you can do is garnish wages. Other then that arrears can accumulate but there is no way to collect if the person doesn't have the money at that time. Arrears don't go away they last a lifetime and can be levied against a persons estate if needed.

Assuming there was proper legal notice, the fact she merely refused to appear or answer any legal notice is not a reason to have the case reopened. She may if she feels something was not listed properly, or if her or your earnings were not listed correctly may ask for that to be reviewed.

Remember she can ask for everything to be re-opened, and that is where you have an attorney who will say basically NO, and fight to not open it back up.

I would first be sure not to be nice about support, if she is late, she is late, if she is not paying properly, keep that enforcement up.

Thank you for your comments.

Regarding taxable monies; I believe the IRS allows the money required to set her up in her new apartment (furniture, rent, etc) to be deducted by me and so taxable for her. We also paid spousal support up front by paying off huge credit card debts (she hid). Legally half of that was my responsibility and half hers - her half is support, and taxable.

In California, as I understand it (but not well - which is why I am here!) for 30 days after the default it can be completely reopened for any reason. After 30 days it can be reopened (set aside) for cause only (CCP 473(b): Mistake, Inadvertence, Surprise, and Excusable Neglect. These seem to be pretty strict - but I was wondering if the courts are strict or loose with them. I guess it is not so much a legal question but an application question.
How do the courts respond?

I guess I have been allowing her to pay much less than required to keep the screaming down and to keep a better relationship - we see each other often - our boys seem to do better with the idea of us all together.
Thank you again for your time and comments.

Unless it was listed as support then it isn't likely to be charged as support. It should have been seen as a settlement. How was it made into support?

We both would have left with approximately $15,000 in debt, $30,000 total. I paid the debt in full and it was listed as prepaid support.
So (the math is just an example - not actual) instead of my wife getting $15,000 of credit card debt, and also receiving $5,000/ yr in support for three years (the same $15,000) - the debt was paid in full and her share was allocated to spousal support.

That's rather odd. Was there not many assets from the marriage ?

There were few assets. The house was in my name - purchased 15 years prior to the marriage and it declined in value from the date of the marriage to the separation.

We had 2 cars of approx equal value. No investments. She kept her retirement and I kept mine - again about the same.

The primary community property was debt. I took out a second on the house to pay it off.