GOD!! who ever suggested that case to you must really be new at making pcs.
Get a standard PSU, I don't think techcom is that bad for a standard user in india, they aren't the best PSU makers, far from it, but still they dish out standard cheap crap. A 450W PSU from techcom comes for about 400INR with all the required cables for a 20+4 plus 8 and a PCIe Power pin.... so it ought to work with atleast one GPU.
If nothing works, go get one of them and use it.
i will definetily buy 450watts thanq