How much would it cost to replace the alternator approximately in this vehicle?

We don't get involved with that here because there's way too many variables. I looked up your vehicle on rockauto. Com and found a wide range of prices all the way up to $531.00 for a remanufactured generator. I guess when you're really proud of your parts you can charge whatever the market will bear. Since this is a discount mail order supplier, you can expect a generator purchased locally to cost more. One of their generators is listed as low as $93.00.

There are at least two different output levels so you have to determine which generator you need. At those prices I'd want to see the results of the tests that confirmed you need a replacement. There could be wiring problems, the battery could have a shorted cell, or something could be draining the battery when the engine is off. When you said, "Car not holding charge", the generator is not the first thing I would think of replacing.

We also don't know the shop labor rates in your area. To keep up with taxes, government regulations, expensive equipment purchases every year, and on-going advanced training, most shops struggle to survive when charging around $100.00 per hour. Most shops use a "Flat Rate Guide" that lists the hours it should take to do the job. That way they all quote you the same time multiplied by their hourly rate.