You'll be absolutely fine. Here's the furthest I've ever pushed an Antec PSU:
A four-year-old, dusty Antec 380W psu, it was one of Antec's cheaper units that they gave away with cases for next to nothing (i.e. the case with the PSU was price-competetive with similar cases sans PSU)
Anyway, at some point after digging it out of the parts box, it ended up powering an overclocked Core2 Quad (95W at least) and an 8800 GTX (155W spec). More than a few splitters/adapters were used by the time I was done, because the machine also had three hard drives, three 120mm fans, an SSD, a DVD drive, a seperate soundcard, wireless-G card and (as the cherry on top) a pair of XBox360 controllers.
It's probably not good to run a PSU at full load, but somewhere around half load is what you should aim for. Your 77W cpu and 130W 7850 wil probably push your system's total peak TDP up to around 275W, but peak TDP is really is rare these days. When the GPU is at full load, the CPU will likely be running cool, waiting for it to finish frames. When the CPU is running flat out, the graphics card probably isn't even running a 3D application these days. I bet you could run your 7850 system off a 250W FlexATX Pico PSU (from a decent brand at least), not that I'd recommend it, of course