90 DX question

The drivers side rear suspension is all jacked on this car. The part was cracked when the car slid into a curb. The pictures are shown below, the weld is cracked and the wheel is bent severely because of it.

I would like to know what the specific name is of the part, and if anyone knows where I would be able to get a replacement, and about how much would it cost.

We tried to bolt a brace to it but still no dice.







Any help would be great!