Should I sell or hold on to my one rental? Need help!

[Jeremy Mahan]

I currently have one rental that is 500 miles away in the town where I went to college.  I charge $890 for rent and pay $670 on the mortgage.  I live near Houston now and would like to start investing in this area.  I have had the rental for over 6 years and haven't had any problems with it.  After doing some research, I believe I can sell my rental for about $95,000 and I owe $70,000.  Should I sell my rental and use the money to invest in the Houston area, where I live, or just hang on to the rental and save my money for another one?  Any feedback would be greatly appreciated.