The screws you mentioned fine-tune the tension of the return springs on each arm. If you want, you can try fixing the sticky-brake problem by adjusting these screws.
There is some more info on how to adjust brakes here:
http://www.parktool.com/repair_help/...arbrakes.shtml
Brakes are a definite safety item, so if there's any doubts in your mind about how to do the adjustments, at least have a shop eyeball it for safety issues when you're finished. If you do get a tune-up, the shop will typically
- adjust the bearings that the cranks, wheels & fork rotate on (this often has a big positive impact on the longevity of these parts)
- make your wheels as straight as practical (the wheel rims double as the brake rotors for most bikes, so straightness helps with getting the best brake performance)
- adjust the brake system for best performance, and hopefully no howling noises or incidents of the brake pads eating your tire
- adjust the shifting and drivetrain
- lube the chain, air the tires, and often some amount of cosmetic cleanup
Good to hear you're getting equipped. Does it get muddy where you live? If so, that chain cleaner should come in really handy