Need spring perch and coil spring

My girlfriends 1999 clk320 needs a passenger front spring perch and coil spring. A search shows me she's not alone. Can someone point out a supplier that I can buy this from? I'm assuming there are no used ones around? Not sure if there is a rubber seal in the perch or not but would need that also. I found a mechanic who says he can weld that on. But he wants me to get the parts. Has anyone done this before? Just wondering how tough this job is and if it requires a qualified mercedes tech or just a good auto welder? Any help greatly appreciated.
Gerald