CPU Upgrade:Intel® Core™2 Duo Processor T9500(6M Cache,2.60GHz,800MHz FSB) 35nm This has an even lower tdp of 35watts overclock results will be easy up to 3.0ghz :) click here
Hard Drive Upgrade:256GB Crucial RealSSD C300 2.5-inch SATA 6GB/s
The fastest SSD hard drive on the planet - at a nice price too :) click here
Full Ram Upgrade:8GB Kit (4GBx2), 204-pin SODIMM, DDR3 PC3-10600 memory module
8gigs of ram and you will be able to load yourself onto your laptop :) click here
Asus k50id Fully Stripped: (K50ij same build)
Asus K50id | Ram Upgrade: (K50ij same build)
Note: If you have no experience with this, I recommend you find someone who is a qualified upgrade technician and knows what they are doing or get in touch with your Asus repair centre and request them to do it for you.