Originally Posted by CRussel
A wireless repeater is fine, but the single biggest determinant is what kind of "WiFi" you have. The various versions are 802.11a, 802.11b, 802.11g, and 802.11n. The difference in range is substantial, with 802.11n having by far the greatest range. The going price for a good 802.11n router is ~$100 USD last I looked. You can easily get them for less, and you can spend more if there are specific features you want (such as dual-band coverage).
Which is fine provided you know what you're doing with installation and setup... Sky provide a router with username/password already set and expect that to be used... and their tech support can be less than helpful if you're not using the supplied equipment... and if reasonably current then Sky provide 802.11n as a matter of course...
The biggest determinant for range in the UK is usually the construction of the residence... wood framing etc is very uncommon in the UK and interior construction can range from brick through breeze block to chip board, all with or without metal supports... one of the worst ranges I found to be due to a fine metal mesh embedded within all the internal walls of a friends flat (that's an apartment for those in the US) and it acted like a Faraday cage...