Taxes, Taxes Go Away!

My head is spinning. I've been doing my U.S. Taxes for the past two hours. I sold my house this year and I am afraid I willl owe tax on some of the gain because I rented it out for 10 months a few years ago. It seems that if you rent your house out, that portiion of the gain is not tax exempt. I'm not sure if I have to figure out how much it gained (or lost) during those 10 months, or if I'm supposed to multiply the gain by the percent of time it was rented for. I have so many questions on just this one topic that it is becoming clear that I will have to see some sort of financial advisor at least as a consultation. I really don't want to pay to have them all done as that would likely cost over $1,000! This dual citizen thing is supposed to be an advantage, but so far it is just been a big pain in the arse. I suppose if we ever want to move to the States, we'd have to do this anyways. Well, back to the grind.