RE: accuracy vs inexpensive ammo
More than likely you can find a better shooting bullet....and probably for a bit less than $55 a box.
If you can't I would suggest selling the rifle and getting another. While 2" at 100 yards will kill game all day I see no reason to spend your hard earned money on a rifle that should be shooting better than that.
Like I said before though, you should be able to find ammo that shoots better than the groups you are getting now.