Is there any way I can reverse the use of a wireless access point into wireless adapter for my computer?

Only if it has a "Bridging" mode. Most do not. You can also look for WDS mode, which is a "wireless distribution system", but again, most home routers do not support that mode.

Some routers can be set as AP or Client, but again, they are not "mainstream" routers. I use two units for a 400 foot wireless bridge for my 10 mbit network. These only cost a few dollars more than Linksys and similar, and sometimes can be found on Ebay

Edit:

There are similar units to this one on Ebay as well, not just this vendor, so shop for the best bargain if you are interested in these types of units. Make sure it supports AP Client mode

On some AP models you can change them to be wireless bridges. That is what you are looking for in this case. How it works in you have a wireless router or another AP broadcasting the network. The bridge then acts like a wireless adapter only it connects to the PC through an ethernet cable. I suggest looking to see if your model has this capability. If not you might be able to upgrade the firm ware to a open source version that provides that feature.