Changing from glossy to anti-glare

Is it possible to change from a glossy (1440 x 900) to a hi res anti-glare(1680 x 1050) by yourself?

Where can I buy the parts?

How long have you had the current system? Maybe you can return it for a system with the hi-res/anti-glare.

Apple has a 14day return policy.
Apple Sales and Refund Policy

PS: I'm not sure if it's possibly or not. sorry.

You can't go up in native resolution without changing the whole screen. The resolution choice is a technical limitation of the screen itself because Mac OS can set any resolution supported by each individual screen.

There are some companies that will convert your glossy screen to an anti-glare but I don't know if they are any good. All they do is replace the glossy screen with a matte one so you will have the same resolution.

If you really want the new hi res anti-glare screen then you might want to think about selling your current computer to help reduce the cost of a new MBP. It sounds like your current Mac is recent so you can probably get a good price for it. Macs hold their price pretty well so the cost of a new MBP probably won't be that great.