UPS for mild gaming usage

I have a microtek 600va ups which is dying. I need to know whether I should buy a new one or is there a option to buy only batteries? In both cases, suggest some good models.

I have shortlisted two models based on customer reviews:
1. Circle 600va UPS on amazon

*www.amazon.in/Circle-600VA-Micropr...&sr=1-2&keywords=ups+for+desktop+computer#Ask

2. Luminous UNO 600

Luminous UNO 600 UPS Price in India - Buy Luminous UNO 600 UPS online at Flipkart.com