theres a nack to it mate,but if i was you the easiest thing is go get someone to give you a lift to get a window from a scrapyard or salvage yard,20 quid max for a window, smash yours and fit the new one,20 pound is cheap really,and well worth it,,but before you smash...
cover the window in tape so it dont make a mess that way there wont be to much hoovering to do