I've got my router plugged into my phone socket at the front of my house. Trouble is I've got very little wireless reception in the garden and back of the house.

Can you get a booster box to put in the middle of the house the boost the signal?

i think you can.
theres these
http://www.misco.co.uk/applications/SearchTools/item-details.asp?EdpNo=522994&CatId=283
i was going to get one, but going into the routers settings and changing the channel number can help somehow. thats what i did, and its better, not perfect though. so never bought the booster thingy. can't comment on how good it is, but they do seem to exist

Plenty of different signals boosters available although I don't know much about them. Just read lots of reviews

Common and easy to get. More than often known as wireless repeaters.

It's a good idea to get the same make of repeater as the router you already have - that way they should work together more easily

Thanks guys, I'll get one of those then!

to use an access point you need to connect it by wired network to the router. The wired connection can be by cat5/cat6 network cable or by networking over the mains network using a pair of Devolo HomePlugs or similar. I use D-Link Wireless G AirPlus Access Point DWL-G700AP which has very good signal strength I buy these very cheaply as reconditioned items off an ebay seller. This type has the big advantage you can connect a high gain external aerial on it.

See Ebay item 290559427155