Help on RN-MSN process

Ok... right now I am in an RN program at San Antonio College. I eventually want to get a BSN and MSN at the UT health science center SA. When I graduate and become a RN, which route is a better route to take RN-BSN or RN-MSN early master's degree!?!? What is the difference between the two? Is it better to take the 2 semesters to get my BSN and then go back to get my MSN? OR go straight to the MSN? Can someone give me some info about the RN-MSN process? IM CONFUSED!!!