Yup, stems come in different lengths and can change your position on bike quite drastically. They are easy to switch. Be careful about buying a very short stem, it can make your bike feel very squirrelly. How long is the one you have?
Seatposts can come with "setback" which in fact gives you the opposite, bringing the saddle further back. You can also slide most saddles back and forth on the rails quite a bit to adjust the fore-and-aft position. The rough rule of thumb however is that the saddle should be positioned so that the front of your knee should be directly above the pedal spindle when the pedal is in a 3 o'clock position (google KOPS and bike fitting). But if your knees don't hurt, I wouldn't worry too much about this being accurate.
Winter riding is much less about badassery and much more about bundle-uppery. - malkin
1995 Kona Cinder Cone commuterFrankenbike/Selle Italia SLR Lady Gel Flow
2008 white Nakamura Summit Custom mtb/Terry Falcon X
2000 Schwinn Fastback Comp road bike/Specialized Jett