NIB-1 & NIB-2 Addresses

I was trying to figure out the pathetic browsing speeds I experience on my broadband connection and found out that I'm on NIB-I network. My IP address starts with 59.xx ... and my speeds are thus limited to about 512 kbps.

Someone suggested that if the network provider switches my account over to NIB-2, to have my IP address starting with 117.xx..., I'll be able to get speeds in MB/s. Now apart from the obvious long-forms, I have absolutely no clue about what these guys were suggesting.

My questions are -

1. How do I determine which NIB I'm On.
2. How many NIBs are there in India (is that a stupid question?)
3. How does one switch between the backbones (if at all).

Looking forward to your responses.