First thing is to decide what you're going to use on the bass itself. There's a wide array of both attachable microphones and piezo pickups. Do your research to decide if one or the other would be better for you (or both).
Once you've figured out what you're going to use to get the sound electronically transported from your bass, do some more research and decide if you need a preamp to go with the pickup/mic of choice. Bob G's site has good info on this: Link Removed
Also, keep in mind that since the instrument itself resonates, there is a much stronger chance of feedback (that's another technical issue). Double bassists tend to use smaller cabinets (many suggest a 2x10 or smaller speaker configuration) since the bass itself is a hefty piece to lug around. As far as how much power you want the amp to have, keep in mind that many venues where you would need a lot of power to be heard have their own house system which you can plug into, with or without your own preamp, DI, etc. More power = more headroom, and tends to decrease the feedback by allowing you to keep the gain lower while turning up the volume.
Take all of this into consideration and compare it to the size of your pocket book. There isn't one right answer to the amplification question; if you think your EB rig will work, give it a try. You will either like it or not. If not, then the search continues.