As
@Yellow Saddle said, freewheels can be a bit of a pain to remove. I'm assuming that you have the correct freewheel removal tool (as you said two prong I'm going to assume it's a Suntour one), as otherwise you're on a hiding to nothing.
You definitely need to clamp the tool into the freewheel with the quick release as they have a tendency to not stay in, and if they slip out you're going to damage something. Also you will need a fairly long handled wrench to get enough leverage to remove it, I generally find I can't remove them with my 1' wrench at all, so I use a bench vise, to clamp the tool.
You do have to be very careful, and the vise I use is metal and held in with 4 coach bolts, I also use some wood blocks cut to size to make sure the tool is level in the vise before fitting the wheel and QR.
Honestly my suggestion would be simply to take it to your LBS and ask them to remove it for you. Firstly if they wreck the hub that's their responsibility, not yours, and they'll likely have the experience, tools and necessary pairs of hands to do it. Should take them no more than 5 minutes, so it's a walk in job.