i have two computers in my household, one downstairs and one up. I'd like to access the data on my downstairs computer through my upstairs one. I have both computers using wireless adapters connecting to a wireless router in my room. Do i need any more hardware or can i work with what i have to achieve a wireless network between the two?

No additional HW required. Make sure both computers are in the same Workgroup, create a Share and check that the IP address range is trusted if you have any firewalls.

Grumpy