A quick guide to focal lengths:
(Note: The figures I'm quoting aren't actually 'true' focal lengths but '35mm equivalent ones, as if you were using an old-fashioned film camera. However they're the ones which you'll normally see quoted anyway).
A cheap 'point and shoot' camera, with no zoom facility, typically has a lens with a focal length of between 40mm and 50mm. (So you can think of such figures as 'normal').
A 'wide angle' lens might have a focal length of 20 to 30mm.
An 'ultra-wide' (or 'fish eye') lens has a focal length of perhaps 12mm.
Going the other way, a 'short telephoto' lens, typically used by portrait photographers, might have a focal length of around 135mm.
A 'medium telephoto' lens, used (say) for picking out architectural details on a building, might have a focal length of 300mm.
A 'long telephoto' lens, used by sports photographers for capturing the action at Lord's (for example) will have a focal length of 500mm or more. [NB: Such lenses can cost thousands of pounds!]
Any lens that doesn't have a fixed focal length is a 'zoom' lens. The lens on your camera is a 3x zoom (since 55mm is about three times 18mm), going between 'wide angle' and 'normal'. [Note, though, that the 'zoom' figure alone doesn't tell you anything about focal lengths; a 50mm-150mm lens would also be a '3x' zoom lens but go between 'normal' and 'short telephoto'].
The rule which applied to 35mm (film) SLR cameras still seems to apply to digital ones: i.e. there's little point buying an SLR camera unless you're prepared to spend at least twice what you paid for the camera on additional lenses (and, particularly if you require 'long telephoto' facilities, often much, much more). For example, Jessops sell your camera for around £280 but an 18mm to 300mm lens (16x zoom, from 'wide-angle' to 'medium telephoto') costs around £500. A professional-quality (non-zoomable) 500mm lens will cost you over £8000!