GardenBanter.co.uk - Preparing weeded area for turf

Hello

I have an area of garden that I wish to turf and would be grateful for some help with how to prepare it.
The area is approx 30' x 30' and has lots of weeds.I keep digging them up and have put weedkiller on them many times (with little effect),then i dont get the time to complete the job and the weeds come back.

Can i dig out most of the weeds and turf straight over ? someone suggested putting black polythene over,waiting for the weeds to die and then turfing ?
Will the weeds grow thru the turf or will the turf prevent this happening ?
Can i rotavate the blighters over ?

I really know nothing about gardening (see my username for my speciality) and my back wont stand much more weeding.The end result just needs to be grass not an immaculate 'lawn'.

Here is a picture link to give you an idea.
http://i41.photobucket.com/albums/e...pe/DSCN0004.jpg

Any help would be greatly appreciated.Regards

Rich.