How to protect my assets as an underinsured motorist

My husband, daughter and I were involved in an accident last August 11, 2007 in Nebraska on our way home to Colorado. All of us ( including the other driver) walked away uninjured. The other driver stated he was fine. No ambulance was called. My husband lost control of the vehicle and it is a miracle we survived. The accident was my hubbies fault. We received a letter from our insurance company stating that there may be a demand for more than our policy covers. ($50,000) Upon contacting the Insurance Company (Shelter) they stated the other motorist has retained a very high powered attorney. The attorney has asked for our policy limits. The claims adjuster feels he may be trying to get underinsured motorist to kick in. He has $12,000 in injury claims so far. The other motorist is very obese and is a diabetic and is claiming an eye problem due to the accident . The adjuster feels this was a pre-existing problem and has requested his last 10 years of medical records. I AM SCARED TO DEATH. Is there anyway to legally protect our assets from him. My husband is the sole income for our family. We have no savings and some equity in our home. My hubby was seriously injured last winter on his way to work falling on all of the ice we had in Denver. ( Compound fracture requiring surgery) he also is scheduled for a hip transplant this summer. I worry about my daughter's future if we end up with a judgment against us. Thanks for any advice or help you can offer.