Basically you can find many random and generic UPS at nearly any computer shop and there are lots of them scattered around in the streets.
First of all you're gonna have to figure out the type of UPS battery you need. I suppose the router doesn't consume much but the notebooks do.
Going with an 800 VA + could do the trick as long as your components need to stay a couple minutes until the private generator comes on.
I recommend you to check this page:
PC and Parts as I always buy my stuff from there. I always bought the PCE brand and never went wrong with it.
Good luck and welcome to the region!