Should I get home improvement loan or refinance with cash out?

I want to refinance my home to take advantage of lower interests rates. I also want to renovate my house since it has severe structural problems.

Should I refinance and get cash out to use for home improvement or should I refinance without cash out and get a separate home improvement loan?

What is the difference between the two scenarios?

Where is the best place to refinance my auto loan?

When I first got my auto in March 2006 my interest rate was 17.9% I refinance in September 2006 with E-loan for a rate of 11.04% we recently bought a home and our finally establishing some credit. So I think its time to refinance again. Does anyone recommend a great place to get a great rate?
Thanks I really appreciate it!