Wait a second. You can't set up another tank, and then just throw the fry in. You'll need to get it cycled. Do you have a filter for that tank? If so, start running it alongside the one in this tank. That will get some beneficial bacteria on the filter.
I would personally say she has about a week or so to go. Her gravid spot isn't THAT dark, and she isn't hugely fat. I wouldn't keep her in the breeder net for all that time. The most I'd recommend you keep her there is three days, after that, let her out for at least 24 hours. Try not to put her in the breeder net more then twice. You could also just let her give birth in the tank, and scoop the fry out. You have lots of plants, they should be able to hide. It'd be better for the mother too. Then once you have your small tank set-up and cycled, you can move her in there for the next batch and keep the fry in there, and it will be better all around.
Also, for salt, aquarium salt is best. Table salt has additives that aren't good in bigger amounts. Also, as Chill said, not all fish can handle salt for long periods of time. Just be patient, and let her give birth in her own time.
Try to keep the stress off of her. What other fish do you have, size tank, and water stats?