Well god (CESC in this case?) ups is the best that i cannot suggest about it
APC back UPS has two slots. one where the phone connection (RJ45 goes in) and the other to which you can conncet the modem (RJ45 out to modem). power backup is 20 mins for 17 inch screen. they have advanced model, check them out.
better is to take microtek sine wave inveretr (13K) + battery 5k. will provide 6 hrs + power supply to PC (enough to trade indian markets) and around 12 hrs to the house on low load (no fridge, washing machine etc). u will find this on the road from bentink street to chandni (is it ganesh chandra avenue?)
if yo want to run your AC too, they are there from other companies and come for around 25K.