Some problems with this idea are -
1) A "car remote" has maximum range of around 60 yards (most are 10 yards). You will either need something more powerful or some sort of cell set-up like mobile phones; you could even use a mobile phone. CB radio also comes to mind.
2) To turn your light on you will need the receiver on constantly, this means a source of power like a wall socket or solar set-up.
I am not sure of your exact application but if you just want a beacon to find something in the dark then the light does not need to be on constantly.
Solar cell, lead acid battery, blue led light that flashes on for one second every 20 seconds, LDR (switch off during the day). This should flash a blue light enough to use as a beacon and providing your solar cell does not get too dirty it should last for 5 years or more without maintenance.