You can't really SLAM as much without a pump, but you can keep your FC elevated and kill the algae. Just dose to SLAM level and brush the pool, get the water moving as much as you can. You will at least keep the algae dying while you wait for the new pump and won't go backwards, even if you aren't moving as quickly forward as you would like.
Sorry that this happened, but keep on keeping on. You will get this!