I believe, but could be mistaken, that the UCMJ must be changed by legislation. Not sure whether the DADT repeal addressed that.
Yes, the UCMJ is actually part of the US Code, (USC 10). And yes, to amend the UCMJ, legislation must be passed by Congress and then signed by the president (or passed by overriding a presidential veto). DADT repeal did not amend or reverse Art. 125.
However, as I explained just above, the UCMJ - like any other law - can be modified, or struck entirely by the judiciary exercising judicial review. To some degree, this has already been done to Art. 125.
Even before DADT's repeal, homosexuals who were "caught" violating Art. 125 could only be prosecuted under certain conditions defined in a case called US v. Marcum, which was heard and decided by CAAF. Marcum sprung from the Supreme Court case, Lawrence v. Texas.
Wait till May
You are correct and it won’t be changed with this congress. Hopefully, West, Hunter etc. will be able to throw some monkey wrenches into this process.