Maggie:
In theory, you can use any playback machine with Dobly to transfer those tapes. Best thing to do is to experiment and see what sounds best.

For everybody else:
There are still planty of companies making analog cassettes. There is little danger that the supply will disappear for many years.

As for reel-to-reel tape, there are three different groups in Europe and North America who are planning to start making tape.It's my guess that all three won't make it to production, but at least one will probably start selling new tape within the next six months.