First Train (grown up) Train Set

I just purchased my first train set (over the net) a Bachman Special Forces, I then visited the local hobby shop (90% railrod items) for more track ( have lay out planned) I noticed there was only a small section of Bachman items only track, purchased and ordered some items. To mack a long story short put some track together and ran, the locomotive seems to be a little on the doggie side, then I started looking on the web for articles about contolers/powerpack and locomotives, would like to upgrade the locomotive and power source and need advice?
Thanks

For DC power packs, at fairly reasonable prices: MRC.

Best plastic locomotives, in no particular order: Atlas, Athearn Genesis, Bachmann Spectrum, Life Like Proto 2000, Broadway Limited Imports, Stewart, Kato.

Next you may want to look into DCC.