Your best bet is to speak with a local lender who can give you some advice about your specific situation and what loan programs are open to you. Make sure you consider the total cost new loan vs. old.,not just P & I (i.e. make sure you are looking at total payment including PMI which you may not be paying now but might have to with a new, higher LTV loan as well as closing costs, interest rates, etc).
Also consider how long and why you plan to stay in this house. See the blog post I wrote a few days ago (linked below) for more information about why you could even be better off selling and buying a new home that fits your new needs vs staying in your current one.
Good luck with your decision.
Bob & Richelle Ward, Realtors, ABR
Prudential Connecticut Realty