How long have you had your oldest card for? Yes I know its a store card...
As many folks who know me, have an idea of what im going to say... Right @averagejoescredit?
If youve had one of those cards for at least 6 months... and the fact its not visa/mc..... id consider trying for a Discover card or even an Amex Revolver... At this point a charge card wont necessarily help you... Personally im all about Discover.. sign up for the free credit scorecard for one true FICO score a month (and its different CRA than the one in-account btw) now .... and if you wait a little bit try the prequal....(im assuming one of your cards is at least 6 mo old)... Reason i suggest CS and a slight wait is Disco will use the SP pull from CS to target offers and it takes a few days for it to propogate (IMHO) .. You may get offers in your email within a day or so... telling you whether you have a chance for a secured or unsecured card... Tend to think unless you have a fresh BK or baddies.. you have a good chance of possibly an unsecured disco but if you dont mind the secured flavor, its not a bad card to have and they usually graduate pretty quickly as long as your scores are moving up...
-J