1 HP is 750 watts (give or take) so a motor using 3.2A at 120V isn't generating even a single HP, more like .5HP at 100% efficiency (and that's not happening).
120V at 15A is 2.4 HP, so that's the max load you can handle. Since there are VFDs that take 120 in and spit 240 3 phase out that's also an option (albeit a little pricey), so something like a nice Clausing, Rockwell or smaller Bridgeport are options, even a used Enco RF30 . Keep looking around, I picked up a nice Hardinge horizontal with a vertical head (and full set of tooling) for something like $750 a year or so back and there's not a lot of stuff you couldn't do with that rig.
Looking at it the G3102 likely wouldn't trip your breaker. If it were 3 phase and you used a VFD you could be sure, the slow start on a VFD is a lot easier on breakers than the surge from a direct connection.
But in summary I'd suggest getting as much mill as you can - you may not always need all of the travel but not having it when needed can hurt.