I'm sort of like that and have learned to do things however I can. I would try to gradually move from pen and paper over to computer; maybe write and type paragraph by paragraph? It could be that once you're started on writing there will be enough momentum to keep you typing just to get it all down?

I would do a lot more typing, start a journal maybe and just type, for yourself and where it doesn't "count". I use to have trouble with having to have written journals perfect, no scratch outs or less than perfect prose :-) I always quit until I started using Julia Cameron's, Artist Way, book. http://www.rambles.net/cameron_artist.html