update with as much info as I can

It's a 1983/84 S/W L series awd 1800... manual, tan colour (no bull bar although it used to have one) The clutch needs work, brakes are Ok, tyres are good, everything works except the AC. It has been used these last 16 years (5 days a week - every week - barely missing a beat) for my husband's cleaning business. It has a few dents on the bonnet and drivers side panel, (where, one night, some clowns chose to run over the bonnet and roof, smash the original windscreen and mirrors, and kick driver's side panels... arrrggghh). It has some visible rust near hatch door. And inner passenger door. But overall, the body is still semi-decent shape (technical term that)
The engine drips a tiny amount of oil.. and has always lost a bit of water - needing top-up every now and then - but has needed topping up daily these last few years; although there is no obvious water leak. It has a very strange 'quirk' which is, that it will suddenly, abruptly, on a day of it's own choosing, empty the entire radiator......... And then once the radiator is refilled, with no leaks anywhere, it will be fine for 4 or 5 or 6 months (still requiring daily top ups) until, suddenly, no warning, it will empty water again... maybe 2x a year this might happen.
This last time, it did it again... but now will not travel more than 10-15km before needing water - and once radiator is filled, it will stay filled, overnight, no leaks to be seen... until car is driven 10-15 km and will again empty.
So enough is enough for us... time to move on.... any thoughts/help gratefully accepted.
We are looking at getting a small car, either something like a Mazda 323 or Subaru Imprezza Hatch.. 98 to 2002 models, around the 5-7k mark .... any thoughts and suggestions from you guys for the Imprezza will be most helpful - ta!
Cheers.