Zoom lens for NikonD3000
I was hoping to use a relative's Sigma Zoom lens for an upcoming Tiger Safari with my Nikon D3000. However, its an old lens and when you attach it, you get a message to say that the lens needs to be set to the highest F-stop value (aperture I think?). This is not ideal and I'm concerned this is going to render it pretty useless. As its an older lens, it also doesn't support autofocus or VR.
Can someone recommend a good quality Zoom lens which will work with my Nikon, be suitable for Wildlife photography and won't cost the earth? I'm prepared to pay about 150 pounds.