So I'm living in an Irvine Company apartment right now, and every time my lease has been close to ending, I've gotten a packet that tells me what my future rent will be should I decide to stay, and a notice to vacate should I decide to leave. However, with this new complex I'm in, they haven't sent anything over, and I need to give them a 30 day notice to vacate or I'll be paying month the month. My problem is that notice is due in a week, but I can't make the decision to renew my lease because I had no idea what they're going to charge me next year should I renew it. I went to the office today and they said they don't know what I'll end up paying for my next years lease. Is this legal? Couldn't they just not tell me what I'm going to be paying, have me decide to stay, then increase the rent 100% when I'm past my 30 days notice and effectually HAVE to stay?

They cannot renew a lease with information missing on it at all.
If they don't give you a new lease, it might self-renew (roll over) at the same rate and all other information, which MUST be stated as such in your CURRENT lease. If not, it terminates, and you then are a month-to-month tenant. If they don't give you 30 or more days notice of a new rate (month-to-month), then you owe the old rate until such time as they do.
In CA:
The landlord must give you at least 30 days' advance notice if the rent increase is 10 percent (or less) of the rent charged at any time during the 12 months before the rent increase takes effect.
The landlord must give you at least 60 days' advance notice if the rent increase is greater than 10 percent of the rent charged at any time during the 12 months before the rent increase takes effect.
Did I explain that clearly? It can be confusing.

There are many changes going on in both real estate buying and in rentals right now, and they are probably trying to decide how much to raise the rent. During all the foreclosures, rental vacancies went way down. That drove rents up. Now people are buying again, but it's not really the average home buyer buying. Builders are rushing to build rental buildings. That will increase vacancies. I doubt in the light of all this that you will get a huge increase. But I would trot back over there and remind them what a good tenant you have been.