Cashed 401K had already paid 30% in taxes. How long do I have before paying remaining taxes?

No it is a 401K

If you take a withdrawal in calendar year 2009 you must pay the taxes (and any early-withdrawal penelaty) by April 15, 2010 - just as with all normal income you receive in 2009. Depending on your circumstance, you may have to pay estimated taxes during 2009 to avoid an underpayment penalty. For most people this is not an issue for the federal taxes, as the 20% already withheld may be close enough to the actual tax due to avoid the under-payment penalty. Don't forget that if you live in a state or city that has income tax these are NOT withheld up front, so again you may have to make an estimated tax payment to cover taxes due on the withdrawal.