Hello, dmudgal, Welcome to merawindows.
I am also using smartax MT882 modem provided by BSNL and its working fine with Vista. I am having dlink NIC. It doesn't require any drivers .
Dont use USB , but connect using ethernet. I does not require any driver.
Regarding SMPS, get a good one according to your needs. If your usage is more, then go for 500 W. Always get a good SMPS. Also check Antec brand SMPS , (they re very good but pricewise , on higher side. ) Some fanless SMPS are also available.
But i think what you have quoted are good and suffice for normal use.