2005 Aveo head gasket problems

Well I went to my local garage and they told me that the head gasket needs to be replaced in my 2005 Aveo hatchback with 130 k miles on the engine. The told me the oil was milky with antifreeze! The car runs great still! Should I spend the money to get the gasket replaced with that many miles on the engine? How long would it take to replace and what would the average cost be? Do you need any special tools to replace the head gasket? Any information would be helpful. I actually own this vehicle and would love to be able to run it longer. Has anyone tried those liquid head gasket sealing treatments that you can get at the auto parts store?

Do you have a good working relationship with this garage? Can you trust them? I know a lot of mechanics mean well, but I simply just don't trust them. Having overspent or been screwed by the dealership, I am always suspect of them. So if you have direct evidence and a good relationship, then it's labor (a couple of hours) and a cheap gasket.

Rock auto has a set (more than you need) for 90 bucks
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I would do the repair myself. It's not easy and just means you have to remove a bunch of stuff to get to the head. Here is some example using a generic car.
How to Replace a Head Gasket | AutoMD

It also means you have the right tools the do the job. A lot of wrenches and a torque wrench.

If you plan on keeping the car for a good long time, you should learn to check the fluids (and change them) yourself. It's really not hard to look at the oil and see for yourself, and even easier to look at your antifreeze.

A little Google goes a very long way!