4 is quite a low number.. I mean even in my freshmen year, including seminars (1 credit) I had 5 classes. 3 .. I cant even imagine taking that few.. isnt that only like 9 credits?
Anyway, I dont think the school matters in terms of the W, it will show up on the apps.. but if you have no chance at an A.. you can consider it.. I wouldnt.
Here is why..
You are still going to be above 3.50/3.45 .. the cutoff (I would think) isnt going to be like 3.6102033240445.. so taking that hit wont be terrible. That being said, talk to your professor, tell him how much it means to you and how much work you have put in and see if you can get the A. If not, talk to your counselor.. I think your GPA is already fairly average and taking that hit wont screw you up too much.