Wow, sounds like you are in a real pickle there!
Actually it sounds like the little metal triangle that usually breaks off has jammed the whole latch.
Removing the hinges may help, but the latch is also semi-burstproof, so it will be held to the striker on the centre pillar. Probably nothing brute force can't overcome, but beware of bending the door and centre post. Try pulling all the internal trim off first and manipulating the latch from inside the door, it may loosen the piece of metal, enabling the door to be open from the inside (the metal piece that the outer button presses onto is usually loose and free if the latch has broken internally).
As for the windshield, try Caravelle Imports in Melbourne (see the Yellow Pages), I know they were a Renault accessory, and he may have some lying around. Otherwise if you want a nifty aluminium mesh external sunvisor (new) for a 12 let us know!
Simon