(So this is not just the firmware, but a complete driver).
If this worked out fine, you can enable Network Manager to use it.
If this worked out fine, you need to load the modules: The Atheros AR5007EG (AR242x 802.11 abg) card is a special case.
These devices are supported by the zd1211rw kernel driver.
Ralink RT2561 series chipsets are supported by the rt61pci kernel driver.
The kernel shipped with Cent OS is not the latest and greatest kernel, it is a known, stable and proven kernel that may be a few years old (depending on the release).
Because of this, newer drivers may not be available for this kernel, even though Red Hat does backport newer wireless drivers to their stable kernel.