I just came home to my parents' house after a year abroad, during which I installed Ubuntu 12.04 on my laptop. In that year I was using wired internet via the Ethernet port on my laptop almost exclusively, and had very few problems with my laptop.
However, when I came home I started to use the wireless and the problem started.

Firstly, when I use the WiFi in Ubuntu, the connection is exceptionally weak, usually no more than two bars of signal (judging by the indicator applet) and speed is fairly minimal.

Secondly, using the WiFi for more than about an hour (I haven't actually measured it, but sometimes it's more, sometimes less) causes not only my laptop to disconnect from the network, but any other connected device to disconnect as well. The only solution is to restart the router.

Thirdly, when I do connect to the network, I get an error message telling me that there's a problem with using a .local address (I can't remember the exact wording).

Currently, I am writing this in Windows 7 (on the same laptop) with no issues whatsoever, so it is nothing to do with my laptop/wireless card. It is just a problem with Ubuntu.

This is the router we use, and these are the specifications of my laptop.

I've had a good search already, but not much seems to work.

I intend to try this next, and I will post an update when I have tried it.

I am open to just about any solution, barring buying a new router/laptop/wireless card etc.

UPDATE: This only appears to be an issue when I've used the battery at any point whilst Ubuntu is loaded.