.Co.in do not get much respect from domainers, but these are nice catches. Until the domainer market for .co.in develops more, most of the value will be derived from traffic.
honestly, .co.in is on its way to death.. .in domains are the "in" thing and they are getting all the attention now..
Sell the 3 as a package and you might get a good offer now than later.. You must have paid like $11 for the 3 names.. You can easily get $100 for the 3 if you promote well and reuse that funds to get a nicer .in name..
.in will stay.. The .co.in, .org.in, etc etc are going to be gone over time..