ILLEGAL ENCROCHMENTS

My land about 30 cents has been under illegal encroachments for the past 35 years in TamilNadu. I found that plot recently while I was searching the patta number of other cultivable land, this land came to light. That land was in my grandfather name and I changed the patta name (LEGAL TITLE) to my mother name and my name recently, as all other blood related heirs expired. After that, I visited that land and found that three families have constructed tiled three houses occupying over five cents and living there for more than 30 years and other place on back side is kept vacant. One house construed before main road occupying 60 feet on my front plot next to main road. The site has 70 feet width and 200 feet length, To get back plot for sale, I discussed and requested before the occupants to give 20 feet rode to go back side plot, but, they are not agree to give even 20 feet road to go/sell the back side plot and they are not ready to give any money to settle the matter in their favour. In these circumstances, can I go for file a case in civil court. How many years will it take to complete case in civil court. Will court give "adverse Possession" in their favour. Please guide me to occupy my plot.