If it is the "DWL-G122 C1", the driver can be downloaded from click here but there isn't yet a driver on D-Link's site for the "DWL-G122 E1".
You would only uninstall the software if you were using their Wireless Networking software to connect, instead of Windows own software. The D-Link software would be uninstalled in the usual way from "Control Panel > Programs and Features".
After downloading updated drivers, you would go into Device Manager, expand the Network Adapters section and double click the D-Link adapter to open its Properties sheet. Select the Driver tab, click the "Update Driver" button and then 'browse' to the location of the new drivers you downloaded.