What is this on my car?

I have a 1998 Suzuki Esteem and I have some front end problems. When I reach around 55 MPH, the steering wheel shakes and it just sounds horrible but when I reach about 70 MPH, it stops and is smooth. It has been rebuilt due to a bad car accident. There is something that looks like a lower ball joint on the control arm that the boot is all tore up but all the auto parts store people say it doesn