Hi Panpot,
If you're determined to stay in downtown Toronto, your pickings for quality will be slim.
Chef of India on Eglinton is probably your best bet. Its pretty good, but isn't standard BIR.
The closest to BIR you will find is Shafiq's in Peterborough, but that's an hour out of town.
If you fancy a bit of a walkabout, there is the Little Bangladesh area on Gerrard East. Loads of restaurants there, unfortunately haven't had a chance to try out many of them yet.
Hope this helps a little. Please do tell where you end up going, and your opinion on the food.
Cheers,
Josh