Need wireless solution for my desktop

[Outlander]

I have a desktop and a laptop. The laptop has wireless, but the desktop doesn't. I have BSNL modem Huawei MT 882. So if I buy a wireless modem; what else will I have to add to the desktop to make it wireless as well. My computer guy calls it a dongle, but what is it called in technical terms, so that I can search for it.

My computer guy says I'll first have to get this:

TP-LINK TD-W8951ND 150Mbps Wireless N ADSL2+ Modem Router: Flipkart.com

Does anyone know of any better one. It has to be ADSL and wireless and router.

 

[Outlander]

I've got a ADSL modem router. I used its CD to set up the modem, and set it on bridge mode and use the Windows dialer to connect to the Internet. Right now the modem is connected to the desktop with the cable. What I plan to do later is keep the desktop downstairs and add a wireless USB adapter to it. The modem will be lying alone upstairs, and I'll use it wirelessly with the laptop.I connected the desktop using the Windows dialler, and then started the laptop as well, and entered the 128 bit encryption key (26 letters long) and the laptop detected the wireless link but there was no internet connection. I tried dialling using the Windows dialler in the laptop, but I kept getting an error of username and password. Then I disconnected the desktop connection, and then dialled the laptop connection and this time it connected, and I could open webpages on the laptop. But does this mean that either the desktop or the laptop, only one can be connected to the Internet at the same time. What if I want both to connect at once? What I want to do is use both computer wirelessly (the desktop downstairs with a wireless usb adapter), and I should be able to connect from within Windows using the dialler whenever I want to, while the modem will always be on upstairs, and won't be connected to any computer.Secondly, I've added the 26 letter key when setting up the wireless network. No one will be able to make use of my network, will they?