If you're health insurance covers it...
1. Recommended Sports Dr. in the area
2. MRI, X-Rays are ghetto and wont show much for a back injury, its 2011
3. Physical Therapy!!!! Go to a really good one. Its going to be years of this to make your back better. There will be a lot of "core" training. Depending on what you did to your back, you may have to learn how to walk, sit, drive, bike differently using different muscles. This may be a life long injury that you will always have to keep in mind while doing anything physical.
4. Take it seriously, we all want to be able to bike when we're 60. This injury may prevent that.