A really big thanks to all of you for helpful advice since I last looked, I have just bought my lens yesterday.
I got the Sigma 70-300 mm APO version as you mentioned Genese, It was a bit dearer..cost me £139.99 from Jessops a little bit more expensive than on the net but I was there LOL.
It is a little slow but when my pocket can afford it I may treat myself to a faster one.
At the present I can't justify spending so much, one day hey.
As soon as I got some decent shots with this lens I upload and share.
Thanks to Pete, Marvin, Genese, and Debbie for getting back to me and giving your advice, cheers.