What happens if you reach the Personal Injury Liability limits from a car accident?

I was hit on September 1st 2009 by someone who ran a red light. It took until Tuesday October 13th for her insurance to finally accept 100% liability. My truck took roughly 7,000 dollars in damages and I have been in a rental car since September 6th.

I have had an X-Ray, MRI, six weeks of physical therapy(3x a week), and started a series of three injections in my back over six weeks. The MRI revealed I had two freshly torn disc. I have had a previous back injury from 2004 that required surgery(2005) and the accident has also inflamed that area.

I have a lawyer and he mentioned that my medical could surpass her limit. At the moment we do not know what her limit is through Allstate. He mentioned I may have to claim uninsured motorist on my own insurance. I only have 25,000 coverage.

Here is my question. The lawyer said my case for future medical, pain and suffering, and lost time at work could be worth 75,000 to 100,000. The problem is my current medical/therapy could surpass both her limit and my uninsured limit leaving me with 0 for future bills, pain and suffering.

How can I proceed to get what is owed me if the limits are in fact surpassed?