Cracked Transmission at Mounts. HELP

[JakeBrake]

Okay so when I bought my alero the Rear Transmission mount wasnt even bolted on the engine , the two bolts were loose and the third bolt at the bottom was gone and where the mount brace bolts onto the tranny , the part of the tranny was completely gone , it snapped off , i then replaced my upper engine mount with a polyurethane mount , and then my front trans mount i bought the poly bushing for and had it put it , i had it bolted but because i could not secure the rear trans mount (the two bolts would always come loose whenever i tightened them because the third bolt was not in) the front transmission mount has now cracked the front of the tranny where it bolts on and is not secure at all .... the engine now moves vigoursly as the only mount securing it is the upper engine mount , im still driving it everyday but have no torque and alot of vibration coming from the engine , is the only solution to do a tranmission swap? or could it be welded? and how much am i looking at price wise for a new transmission and it swapped? Thanks guys.