Widows 0 Newbie Poster

I'm having some trouble with bandwidth hogging at my house. We have 3 PCs that regularly use a lot of bandwidth (downloading/streaming etc) and 2 XBoxs that are often gaming online.

My house has a 20MB cable broadband connection (Virgin Media). The modem is connected to the router via ethernet cable, and the connection is shared via a TP-Link Wireless Router (300M Wireless N Router Model No. TL-WR841N / TL-WR841ND).
All the devices are connected to the network wirelessly.

I'm wanting to limit the amount of bandwidth each machine can have so that we can all have some decent level of use out of our connection, rather than just one or two users muscling in on all the bandwidth. I've heard of QoS but my router doesn't seem to have this feature. Also, I've read about software you can install on your router to do this for you, but I don't know how stable it'd be or how I'd go about it.

There is something called a "Rules List" in the "Bandwidth Control" section of the router's management software but again I've no idea how to operate it for this purpose (if you can even do that).

Can anyone recommend some routers with bandwidth management features, or how I would go about it on my current router? Or, any advice on which software to use/how to use it etc.

Thanks in advance