Can you put up a picture of the whole bracket? Lots of us have stuff like that laying around, you might get lucky and someone will recognize the part, or one so close that it could be modified to work.
A weld done by a pro would work fine, but guys who can work with aluminum alloy aren't plentiful. You could try drilling 2 holes to insert heavy wire as a reinforcement, like rebar in concrete, then JB Weld it.

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1986 560SL
2002 Toyota Camry
1993 Lexus