Need Help on buying a WiFi Modem+Router (URGENT)

I am planning to buy a Wifi Modem+Router today with SIM Slot and an Ethernet port.

I will use Airtel/BSNL SIM (both 3G) with it for two or three months. After that, I planning to get a Broadband. That's why I need a SIM Slot and an Ethernet Port. I will be connecting the following.

1 X Desktop
2 X Notebooks
1 X Smartphone

Need your suggestions ASAP.

EDIT: My budget is 5k. Can be extended if it is really worth.