Hi Gauri,
Dont worry, you can prepare idly by using basmati rice that too raw one. what you have to do is, just
soak 2 sp fenugreek seeds for 24 hours and after that you soak rice and udad dal for 6-8 hours. Then grind them. Keep the dough for 12 hours and then make idly.
Surely it will come soft.

The feramentation is important, if it is cold season you can keep the dough for some more time or keep it in the MW. Try and give me a feed back.
All the best.