What kind of lens can I get for my powershot camera to use in low light and faraway

[jfo]

Libby, your Powershot camera has only the lens it is built with.  There are no lenses to upgrade to / change from. 

Here's some quick reading to consider if you need different capabilities from your camera:

http://digital-photography-school.com/should-you-buy-a-dslr-or-point-and-shoot-digital-camera

[cicopo]

Link may be handy but be careful, some of the info (recommended cameras) is VERY dated. S3 IS is probably from about 2005 -2006