rt series

over50

I`m switching from monitor to rt series. I just pulled the trigger on a center speaker. csia6. newegg had on sale for 279. at that price i just ordered the csia6.What i need help with is my fronts. Here are my choice. Newegg has rt7 for 700. pair, or polk ebay rt12 for 700. pair.A third choice is keep my m70. I`v got subwoofer, dsw micrpro 2000. my room is about 11x20. about 40% i use my ht system for dvd and music. I realize the rt12 is the same performance as the rt9. I`m having a hard time desiding if i should buy the rt7 or rt12 or keep my m70series II. Any help or feed back i will appreciate.
Thanks for your help.