Sir I dont know where have you been searching for your solution. But Montgomery road is the place for such job.
They have old remotes in spare. They take out your car installed kit, put it on the so called test bench. Remove the the IC from old remote, reprogram it, resolder it back to remote and it starts working with your original security kit. This job requires 400~700 Rs depending on condition of remote they have in spare
As for the older remote that is dying, I am assuming buttons are not responding. They clean them for only 100Rs and it works great. Plus they drop WD-40 after cleaning so that deposits dont occur inside the button soon.
Hope it helps.