Interior door waterproofing and winder cable refit. HELP!?)

[suffolkpaul]

evenin'

to investigate the borken rear window winder mechanism I had to remove the interior door card and carefully pull away some of the waterproofing material behind. Should i replace this membrane thingy or can I use some form of tape to help secure it properly and keep the water/crud out?

ta.

p.s. the winder cable has snapped...how easy to replace??