Hi
most people graph their stats using MRTG which isnt always for the faint hearted Im afraid.
Its easier with some routers than with others.
All of the routers Ive graphed have needed some additional perl programming (thanks chris).
I believe PRTG may be easier but it is more limited in how much it can graph, but Ive never personally tried it so I cant say.
The Netgear DG834G will allow you to graph data transfer, but to record SNR Margin, sync speed and attenuation does need some additional programming.
Chris is the expert on that and he may be able to point you in the right direction.
However, hes really busy with work right now and is away until after the weekend, so Im not sure when he will next make an appearance on here.
Hopefully he will pick up on this thread in a few days time.