Hi Om,
RX9 by izotope is not cheap but I think they have a trial version.
I have izoptope rx 7 and its very good,for instance you can isolate vocals fairly sucessfully.
If you want you can send me a wav or part wav and i will happily run it through RX 7 and tell u what i did and u can see for yourself whether it would be a success.
Rx has a repair assistant that will give you a suggested module chain u can pass ur song through and it has a music rebalance module where u can bring forward or back the vocals or the drums or the base a few db,
Let me know if u need help
Hugh