In the preview for the next ep. There are what seem to be 70s, 80s and maybe 50s Claras. So I think there are others on the way not just the 3 we have seen so far. One of these is nearly run over by what looks to be the 3rd doctors car.
There is also a scene where Clara seems to be about to do something (move into) some sort of energy thingy.
If I'm making a stab at what will happen I think Clara will "sacrifice" herself to save the Doctor (or Tardis) and end up fracturing her time line or similar so she ends up all over the doctors timeline (past, and future). So the Modern Clara (just a normal girl) is the original who gets sent out to become the others he meets. In other words if the doctor had left her where she was the others would never have existed.
Good news, everyone...
I've invented a faster delivery system for gossip and pornography... now hold still while I inject the internet into your skull.