Try to pick up improved unarmed strike and maybe even improved grapple and stunning fist later on (some fighter levels would help with the feats). Two weapon fighting would let you do the old one-two combo. And if you have an arcane friend, get a minor ring of spell storing (or ioun stone) to keep a few True Stikes handy. That let's you do your full power attack and still pretty much guarantee the (first) hit.
d20 Modern has some good, basic, brawling feats that let you build a decent scrapper even at low levels - so you might ask you DM to look over those.