Hey Michael. These were not very good guitars back in the day. They were made in Japan in the 60's and 70's and did not originally sell for much.
Nonetheless guitars are often "part of me...." as one of my clients told us last week so where we may not see much value others may have memories of that first girlfriend/boyfriend, etc. or what ever and they can be priceless to someone else.
Frank Ford has a great write up on his site FRETS.net where he takes a "scoop" out of the top and replaces it with a new scoop not unlike what Chris is advocating above. That might be a good approach but know in advance it's a LOT of work especially the area replaced outside of the bridge footprint where finish repair and color matching needs to happen to make it right and whole.
Bridges often lift for a reason so be sure to very carefully inspect the bracing to be sure that it's all in place and nicely glued down. More likely is the possibility that because of the lousy, cheap slotted pl*stic bridge pins that over time the bridge plate has been eaten away and is now damaged from the string balls starting to migrate up through the pin holes as the pl*stic pins bent and distorted.
If the bridge plate has excessive wear and that is not addressed any top repair and new bridge will not last very long because the original causation of the bridge lift was not addressed.
To address bridge plate wear when this fix is appropriate for the instrument and it would be for this one is a bridge plate cap. A bridge plate cap is often made from some nice, hard maple and can be around .050 - .060" thick and just large enough to cover all pin holes with a bit of over lap beyond the pin holes. It's easier to predrill the holes in the cap before installation. Installation is done with a couple of locating pins, we use something that glue does not stick to well if at all, teflon, etc. 3/16th" and then with a flat caul under the cap that is aligned with the pins glue and clamp the sucker in place.
After installation and when the top is fixed and the new bridge is on drill with a 3/16" bit and ream for the new pins. You are using new pins, right.
It would also be a good idea to convert the thing to unspotted pins during this process.One last thing that should have been the first thing. Check the neck angle, it very likely may need a reset and that my friend may make the economics of working on this one not work for either owner or you.