Wi-Fi adapter

I highly recommend an Asus PCE-AC56 if you have a PCI slot to spare. Very stable and fast.

From one gamer to another, you have my strongest and deepest sympathy at not having the option of using ethernet. When I was living with 3 friends in a house, we had a similar problem, but it was nonoptional for us. We were going to go to any lengths to secure an ethernet connection for all four computers. By the time we were done there were cables, adapters and extenders absolutely everywhere. Multiple 100 meter length cables running all the way from the living room, through the hall, into the kitchen, back around through another hall, up the stairs, past the bedrooms and into the room with the UPC box. This also included extra cables that ran into everyone's bedroom as some of us had laptops and wanted ethernet while using them in bed too. The entire house was cables.

I bought this one a while back:
http://www.tp-link.com/us/products/details/TL-WDN4200.html
It's a bit outdated now, but it works nice so any of its successors should be good I guess. I used to be skeptical about this kind of WiFi device, but the convenience is nice (no need to open your PC, can easily swap it between PCs) and the connection is as good as with my other internal WiFi cards. Note that this one came with a USB cable, so it can be moved around a bit to place it in the place that works best.

If you're not going to get a pci wifi card, tp-link Usb ones are pretty good, but whatever you get you want it to be dual band

i'm cringing at some of these suggestions tbh. i don't wanna specify which ones really so i don't offend anyone, but some of those suggestions are known to fail fast.

imo, go with anything atheros or intel chipset based if you can. and try and avoid realtek & ralink chipsets --- i'm not talking about brandnames at all such as dlink/linksys or anything like that, that part shouldn't really matter, but the chipset the model itself uses instead.

just google model # + chipset to find out which type each model is.

I have this one, didn't have any issues with it so far (got it a few months ago because my old card failed). It's fairly cheap and should be good unless your internet is faster than 150Mbps or you're very far from your router. My router is one floor above my PC and I have perfect connectivity with my network.

Still, browse the reviews and check the other proposed cards to make sure you'll like what you're buying.