The new Traditions Vortek muzzle-loader shoots awesome and is a fraction of the price. You can get the gun for under $300 then put a $150 scope and get out of there pretty cheap. You can get pretty good out to 250 yards with these new guns, but 300 is a stretch..
You could also buy a different rifle, one in the $650 range and have some cash left over for gear and your wife...