You can retrieve your hand histories on PokerStars by going to "Requests" and clicking "Hand History." Probably select the "1 week" option. If that's not far enough back, just email email@example.com
and tell them what you're looking for.
On Full Tilt, I believe you need to go to their website and look on the player control panel. This link might work: www.my.fulltiltpoker.com/nl/hand-history
I've had issues with it not working in the past, just email Full Tilt support if you can't figure it out and they should point you in the right direction.
Another suggestion is just to play a few games, select a HH with plenty of decision making within it, and use that for review. Reviewing a game a few months ago is more likely to be less relevant and less indicative of your thought process and decision making skills today.
Let me know if you have any other questions.