I wouldn't worry too much about bottlenecking. Given your overclock, your performance should be just fine in most games and you should look at a gpu purchase from the same standpoint as if you were running a 2500k or better. Either pick your price range and shoot for the best card in that range or pick the performance level you want (based on your resolution, desired framerates 30+ and the games you want to play) and shop for the best deal that will provide that level. A 460 SE is a decent card, but you can find a pretty massive upgrade for a pretty good deal.
Of note 560 ti's can be had for about $180 after MIR right now (on some models- imo this is the deal to beat right now), and 69501GB can be had for around $210.