Apple MacBook Pro 15 A1286 2.53GHz Intel Core 2 Duo 8GB Ram 250GB HDD 10.6.8
It already has the ram maxed out to 8GB which is the maximum ram you can install in the 2009 MacBook Pro Models.
The only upgrades you would need for this model would be:
SSD drives make a world of difference in these MacBook Pros and the original drive in this is only 250GB anyway. If you replaced the hard drive with the same sized SSD drive you would not lose any space and yet have a much faster MacBook Pro.
You will need a new battery. You can buy a 3rd party battery for about $30.00 for this MacBook Pro.
If you swap out the hard drive for a faster ssd and add a new battery to this Mac you can have a very nice MacBook Pro for about $400.00 after upgrades.