Can I access EVDO Network with CDMA 1x device?

No, you can't.

Does EVDO device use a R-UIM / SIM card?

No, the device can access the network without a R-UIM / SIM card.

Where can I buy EVDO device?

You can buy the EVDO device at your local BSNL Customer Service Centre.

Can I use this device with Windows Vista?

Yes you can.