Hi Pankaj,
Yes The Dx6i is very much capable of handling Heli's.
More or less the check list for Heli is the same
Get a Heli ARF kit
Get a Tx/Rx
Get a power system (Lipo, Esc and Motor)
Gyro (tail stablizer)
Get servo's for controls (so 3 normal servo's can be any 9gm servo's and one tail servo should be fast )
Now like in Planes all kit's and parts have a certain range and price which is similar in Heli's the more sugar you add the sweeter and stable your heli will be
Go for a 4Ch RTF for beginners and work your way up.
Happy flying
Hellyflyer