You're right about needing to replace the winshield seal, and there are a couple good threads on this here. I'm not going to address any other leak points as these are also well covered in on this site.
But, until then, flowable silicone is the next best approach. This is a special silicone formulation that squirts out easily and sets up slowly. I did this last summer and used 3 NAPA tubes to do the exterior permieter of the upper and lower sides of the rubber. ACE also carries this product.
It took about 10 mins each run, and I slid a small plastic putty knife around the rubber while squirting a SMALL amount of the flowable silicone behind as I went around. Even with my best techinque it was a little messy, but I wiped excess with clean shop rags.
I also did the radio antenna seals, and took special care in the lower corners and lower, outer sides. This did solve my leaks - along with inserting new (PO missing) LOCK strips from Blunt. He quoted very reasonable prices on front and back, (and the lock strips) but since I'm going to replace the windscreen soon, I didnt want to use new seals yet.
Hope this helps!