If the Pulsar is in good condition, as you seem to indicate, it might be best to repair it. A mechanic should be able to work out if it's a head gasket problem or a cracked head and from that give you a cost to repair the engine. It might be better to spend a few hundred dollars on repairs than spending a similar amount on another old car that might itself have problems. Trade-ins are generally passed down the line, from dealers to used car lots, until they are no longer viable and they are then scrapped. Check local used car yards. If they don't have a car for you give them an idea of what you want and they might be able to source one. There are also plenty of websites offering used cars for sale, and they are probably the best place to start shopping. If you need help using the sites, get a friend or relative to help.