The most important upgrade is making the system drive a Solid State Drive (SSD). This alone may double the effective speed of your computer. Extra RAM is a nice second.
Since SSDs are usually more expensive than traditional hard drives per GB, you could explore a 'hybrid' drive, though I'd recommend the fastest SSD that your Mac's PCI bus throughput can handle.
When I upgraded my old MacBook Pro (I think it was also a 2009 model), large SSDs were still expensive, so I bought a 128MB SSD for the main system drive and moved the existing HDD into the spot where the Optical Drive was (with a special mounting bracket), and put the Optical Drive in a cheap external USB case.
I found all the parts on eBay for under $250USD and was honestly shocked at how much faster that MacBook performed.