Also, there are income limits. Singles can earn 75,000, married couples 150,000 - the tax phases out above those figures. Closings must occur by Dec 1, 2009 to qualify. The credit is clalculated on 10% of the purchase price - not to to exceed 8,000.
It is my understanding, and I am sure you can google this to verify it - that the original tax credit in 2008 (which was for 7500, and had to be repaid over a certain timeframe) lasted from July, 2008 to the end of the year, when this new credit became available (but maybe you are correct with your April date)....In any event, If you closed in Feb., you were too early , regardless of the date - it was NOT a retroactive credit, and did not cover all of 2008.
You can always verify this with your tax preparer, if in doubt.