It might be a good idea to first check if the wireless-enabled PC that you are using to remotely log in to the server is connecting to your home network at 54Mbps by double-clicking on the networking icon in the system tray. Although 802.11g Wi-Fi isn't as fast as Ethernet, in practice you can generally achieve around 27Mbps throughput (about half the theoretical speed of the wireless standard).
As Rober Vamosi points out in this remote access software comparison, each application has its pros and cons. For example, while GoToMyPC (download GoToMyPC here) works on Macs and Linux-based browsers, it has pricey subscription fees. Given your situation, MyWebEx PC (download MyWebEx PC here) might be worth considering as it is free -- assuming your PCs are running Windows.
Finally, if your remote computer is running Windows XP Professional, Microsoft's Web site has an article on how to setup the built-in Remote Desktop feature of the operating system.
In our experience, all remote access applications that load a graphical user interface rather than a command-line prompt are a little sluggish. However, you might find one that better suits your needs in CNET.com.au Downloads -- in particular, the Remote Access category.