Congratulations you just started out on what could be a very long painful, difficult and potentially expensive road!
The whole reason people spend so much money time and effort on acoustic room treatment, high end converters and monitors isn't just cause its slutty. It's to make sure the mix you are hearing is as close to reality as possible. What that means is that if your monitors, room etc make the bass really loud or hyped, you will tailor your mix accordingly i.e. turn the bass down. Result being when you play it back on a system that doesn't have the corresponding hyped bass response your mix will have little or no bass. This applies across the frequency spectrum both positively and negatively.
Your best starting point is either spend money on room treatment and the best monitors possible or spend many, many hours learning your current setup which is cheaper but not ideal. By that I mean constantly check mixes on different systems in different rooms. I know some guys get great mixes in crap rooms on crap monitors simply because they know the issues and can account for them, but as I say not ideal.
Hope that helps?!
Macbeth M3X, MS20, FRXS, MKS80, 9U Modular, PolySixM, Supernova, Mopho, Ridgefarm Boiler, SDE 330, RME FF800, Alesis AI3, ADA8000, Adam A7X & Cubase 6 (PC). http://soundcloud.com/opikoort