Sounds like you need a good set-up on your bass. It's always best to keep the bass in the case when not playing. It's also good to store your guitars in a climate controlled room: Monitored humidity level at 47% and you'll be good.
Not sure what you want to spend on an amp, however, here's what I believe to be the best bass combo amp on the market
.
http://www.eden-electronics.com/prod...v/dc210xlt.asp
Keep your eyes open on eBay for one of these. I've seen them go in the $850. range which is absolutely a steal
. If you find one at this price, grab it! It will most likely be the last bass amp you will ever need.