Car has a hard time accelerating from stop signs/lights.

I just replaced my alternator due to my car not staying on when idling. Then I took it in to have the idle raised since it was still stalling when idle. But the problem that still exists is when I'm stopped at a light or a sign, if I lightly apply the acceleration, the car's real****** like it doesn't want to accelerate and continues to due so until high into 2nd gear. It seems to only do this when the car is warmed up, it didn't start doing it until about 20 minutes into driving this morning. I was told it might be an o2 sensor or a fuel filter problem but I have no money to get it properly diagnosed and pep boys told me yesterday that they don't have an OBD I.