I did warn about the bolts and not to overtighten. The torque is only 5lb which is very light.
Did you shear the bolt whilst tightening, or was the bolt already over tightened and snapped on removal? If it broke when tightening, the broken bit will be quite loose within the thread. If it broke whilst trying to unscrew it, then it could be rusted and difficult to remove. Let it soak in WD40. You should be able to buy a new bolt at any garage. Get them to match the thread and diameter. Obviously if a new bolt is longer than needed, just hack saw it to size ... gently file/round the cut end and it will easily screw into the hole.. Now read as below.

Do you have any bolt remaining inside the hole? If it snapped whilst tightening there is a chance it will unscrew with a screwdriver. Use a flat bladed screwdriver that fits down the hole but not too tight against the hole's thread. If necessary grind away the sides of the screwdriver until it fits easily into the hole. Now sharpen the working end of the screwdriver ... knife appearence.
First try pressing the screwdriver into the remaining piece of bolt and unscrew. It that fails then get a small hammer and tap the screwdriver into the remaining bolt so it has something to grip into. Dont hammer too hard, you will break the housing off. Now unscrew.

NB ... you can buy 'stud removers'. These are screw type products which are left hand threaded. They screw down but in the opposite direction to the direction of the bolt. Stud remover has a left-hand thread so as it goes down into the broken bolt and wedges itself to the broken bolt. The direction of turn actually removes the broken bolt since the bolt has a right hand thread. You can buy stud removers in several sizes. The need a drilled pilot hole to bite into the broken bolt.