RIMO in Denpasar is generally considered the place to go for computer stuff. But when I went there a few months ago, I was pretty disappointed with the place. There were almost no customers and lots of people hassling you. I would suggest buying online from a site like lazada.
Couldn't agree more. If you don't know exactly what you want/need you're more likely to get the run around than good service.
Here's what I'd do. Use the web to find the exact make and model you think would be acceptable and then look for it on the Indonesian online shopping sites.
Here's a link for Tokopedia which you can use in English (although the text of the listings will probably be in Indonesian)
https://www.tokopedia.com/p/laptop-aksesoris/laptop?lang=en&pmax=10000000&pmin=5000000&vi=2&ob=3
Make sure you buy a well known brand, as all the main ones have service centres in Denpasar.
