I own a nikon d60 and am looking at buying a new lens?

I would like a 18-200mm lens, i know the d60 is a starter camera but i'm getting into more professional photography and can't afford both a new camera and lens at once. Does anybody have any advice?

Added (1). Thanks for the answers, I'm having trouble finding a 18-200mm lens compatible with my camera, i'm not really sure where to look to find the right one?

Well what exactly do you want to shoot?

the 18-200mm is a good all-around general lens, but specializes in no one area. It is a "jack of all trades" lens if you will.

better would be to get some prime lenses that offer better quality over their zoom lens brothers/sisters

Yes, buy the lens and use it.

Your investment will always be in lenses since they last for decades. Even a great camera like the D60 will eventually need replacing only because of the continually advancing digital technology.

The new Nikon bodies will not be arriving until some time in the third quarter of 2012 due mostly to the earthquake and tsunami in March of this year.

By then the whole landscape of camera bodies will have changed and if you have been saving your pennies after buying the fine 18-200 mm lens, you will be in a better position to make a choice of which new camera body you will be saving to buy.

Designed exclusively for Nikon digital SLR cameras, the Sigma 18-200mm f/3.5-6.3 high-zoom-ratio lens covers a host of wide angle and telephoto focal lengths. The lens includes a built-in motor that provides high-speed autofocus, along with two special low dispersion (SLD) lenses and two aspherical glass elements that correct for all types of aberration. Sigma's super multilayer coating, meanwhile, reduces flare and ghosting and provides topnotch image quality throughout the zoom range.