That clamp looks bent about 90 degrees froward (toward chain rings). Probably will break if bent back into correct position.
If you have more troubles with it or with finding a replacement, PM me your address. I'll send you one of the best performing derailleurs ever built and particular favorite of mine, gratis. The venerable Suntour SL. Bulletproofa and still looks good in a steampunk kind of way.
Best,
Julian