For many pedals and rack comps reviewed go [url="http://www.ovnilab.com/index.shtml"]here[/url]:-
For a decent (if I do say so myself) description of compression and how to go about setting up a compressor for bass go [url="http://blog.basschat.co.uk/setting-up-a-compressor/"]here[/url]
If I were to pick a coupl eof pedals I think are a cut above it would be the Markbass Compressore and the Joe Meek FloorQ.
Can you do more with your compressor? Almost certainly, after all in recorded music the bass is one of the most likely to be compressed instruments in a mix.
Should you do more with a compressor? If you know what you are doing - or are willing to learn - then probably IMO....
A compressor wont 'improve the highs' it will allow you to get a punchier more even sound, that will give you a better than fighting chance against the rest of a band in a mix (esp the kick drum, but in some cases guitars, keyboards etc). It will help even out the inhenrent changes in the envelope of your sound that the bass produces with different techniques.