hi there this is a rite pig of a job!!! as a worked for autoglass for 10 years its still not easy trust me lol
first of all to do it prop you need some square wire and some t-handels or mole grips covered with masking tape as people say you need to undo the nuts on the window to release it from the bodywork but it wont come out because its pur glued to the bodywork to make it water tight and as people say yes the nuts are only there to hold tight as pur sets and drys
here gos first use lots of masking tape around the window to protect your paintwork!!! your need it trust me!!!
run your wire from the top around the window from the out side leaving about 2 foot extra so you can work with it (may need a small screwdriver just to get it right under the plastic be carefull as easy to scratch and if you chip it or crack it its f*@ked as its CAN NOT BE REPLACED!!! its molded around the window as one unit) wrap wire around handels or mole grips and squirt lots of soapy water where the wireis as its needed for lube (ooh err lol) with a sea-saw move rock the wire flat to the bodywork or it will damage plastic or paintwork (be awere the wire may snap) keep doing it till the pur glue as been totally cut and remove the window
the other way is with a long blade from inside but you still need to squirt soapy water in there to made the blade slide or it WILL keep brakin on you and theres not alot of room in there so bloody hard work beleave me
if its only gonna cost you about 60-70 quid then i would pay it as its gonna cost you a hell of alot more to replace it if you brake it
if you got time on your hands then go very slowly and KEEP lookig where your wire IS CUTTING if any probs shout and i will try to help out