Two things you can do:
(1) Continue plugging away at work, and find whatever which way to network, network, network. Strangers may not take you seriously as "retail sales" but someone who knows you may be able to vouch for you as an individual. And to get to that point just takes time, effort and a bit of luck to be at the right place at the right time.
OR
(2) Get out of finance entirely, unless you're so hardcore about finance that you can't do anything else (get out if it, find some other career, and then revisit the finance thing in a few years). It seems like you feel stuck in a holding pattern (or being that high school kid who gets pigeonholed within a certain group when you want to hang out with the other kids). What that means is that you may want to do something outside of finance, anything, to get a different perspective on things (and hopefully have others see something different in you).
In short, you're going to face the same hurdle in b-school admissions as well as recruiting (they won't see your experience in the same light as institutional sales), which is why you need to find something to get yourself out of your holding pattern NOW. This may not mean quitting your job, but finding some outlet outside your job that allows you to redefine yourself -- not only for others, but also for yourself (to see yourself in a different light).