depends on how well the engine was taken care of in the first 150K. regular oil changes with a good quality oil, regular timing belt changes, other maintenance, all documented? if so, you can count on another 150K or more. if not, your mileage may vary proportionally.
good maintenance ain't cheap, but expensive maintenance at a dealer is not always the best, either. spend some more time in here, noodle around and learn. don't expect to get a good car for cheap.
i lurked in here for several months before i bought my 2000 Jetta TDi, and it has over 211K miles on it now. never had a failure of anything in the drive train (engine, clutch, transmission) that affected reliablilty. i did have the plastic drain on the bottom of the fuel filter crack and prevent me from starting one morning. was fixed with a replacement filter in about 3 hours. this was around 30K miles or so, since then i've changed my own fuel filters in addition to oil, oil filters, engine and cabin air filters. Have used BioDiesel in varied mixtures for about 100K miles now without a problem. If used conservatively, I think BD keeps an engine running well considering the fuel's lubricating and detergent/cleansing nature.
little nicky nacky things might occur, such as broken glove box hinges, but how often do you use the glove box??
don't be in a hurry, do your research and you'll find a good car, maybe not in Austin, maybe further away.