No Internet Connectivity Through Router

I'm currently living in a shared house right now, and for our internet, the landlord has us on Virgin Media's basic package, which in theory should be netting us around 10mb (according to the lady that I spoke to on the phone from there anyway). It comes into the house via a cable, then goes into a modem, and then that modem is connected to a wireless router which pumps it out into the house for everyone (at least it tries to anyway - read on!). That's what I can make out from what I can see at least.

Now, when I connect my laptop to said router via a cable, the internet works fine, and doing speed tests, I get relatively consistent results around the 10mb mark that they should be. However, when I try to use the wireless with my laptop, even sat right next to the router, most of the time, the internet doesn't seem to work at all. Webpages just load indefinitely, or I get an error message saying that the connection was reset whilst the page was loading.

On rare ocassions where the wireless does work, and I run a speed test, then I'm lucky to see results close to 1mb, and in my wireless properties, the speed usually says something like 18mbps.