Hello,
The easiest thing to do would be to but a small 5-Port switch. The newer ones are auto-sensing so you can use either a crossover or a stright through cable.
If your PC doesnt get an IP address from a DHCP Server like a router then you will need to assign a static IP address (i.e. 192.168.0.1). You will then need to set a static IP Address on the printer which is in the same range (i.e. 192.168.0.2).
How to set a static IP on Windows 7 (Steps 6 to 10) :
Setting a Static IP Address in Windows 7 - PortForward.com
I am an HP Employee