like OH4CompG said, drop the cradle should help out, then if you can get a grinder to the broke bolt smooth it off, hit the bolt center with a center punch, and a dewalt 9 volt drill (or small drill or right angle drill if a regular one wont fit) and a 1/8 drill bit as a starter bit, maybe you can get a back out in there after this, if not get a bit one size smaller than the bolt and drill it, and then tap it out.
put the one bolt that's still good in the pump and measure how far it sticks out, don't drill any deeper than this, you can put tape on the bit as a guide.
