Doors and Windows - How to replace a window that was in a door...?

We have a rather small exterior door (to a screened in lanai) with a window in it, window opening is about 14.5 inches across and 31 inches tall, with two vertically placed sliding glass windows in it, in aluminum frames, made of glass that has "bubbles" in it/you can't see through it. One frame broke/the top section/slider-we have had it taped - ugh! We have tried for 1.5 years to replace it. Ace Hardware won't fix it, they said it is more work than it is worth to repair or replace the old aluminum frame.
So, we figured just buy the same glass, cut a little bigger, toss the old glass and it's frame and just caulk the new glass in the outer frame on top so we stil have glass on top (it wouldn't slide/wouldn't look great - but better than duct tape!). But, we can't find the same glass.
So, we asked Ace to sell us a piece of glass for the top, do with it as described above, and then replace the glass in the bottom slider frame with the same glass so they match.
Nope, they won't do it, not worth the trouble/old frame might break. What can I do? Should I just take out (rip out?) the whole frame and fill in the whole thing with wood? How would I do that? Or...?

How much do doors cost....? What is the most economical and quick way to proceed? We both work two jobs, money is tight, and my husband is not very handy, but we can manage to do some things with instructions...
Thanks for any help you might be able to offer...

I think the cheapest way out would be to replace the door and frame with a prehung exterior door unit to your liking. The one you have sounds a little dated, anyway. That's where your saved $298 can go.