None of the Verizon netbooks had an external antenna port from the research I did about a month ago. You would be stuck using one of those wireless 'repeater' style amplifiers, which can be pretty spendy.
As for capability, I had an HP 2133 with a slower processor than that HP311. It ran GRLevel3, SN, Delorme Maps, Firefox, and VZ Access Manager under Windows XP no sweat with 2GB of ram. Delorme could be a little slow at times when you were really asking a lot from it, but it was very usable. The newer HPs are a bit more capable than that 2133, so if you can find a model that can at least be upgraded to 2GB of ram, you should be sitting pretty. I will say that of the 4 netbooks I've tried, only 2 really handled Adobe FME very well, so streaming from it could be hit or miss.