New Router

[#1]

I have decided to get a new Netgear DG834G router,however would i get any benefit if i upgraded to a DG834GT 108Mbps,  if I do I expect I shall also have to upgrade my WG511 and WG311 to 108.What do you guys think,worth it or not.?

[#2]

After the wireless b and g standards, is supposed to come wireless 'n' but wireless n seems to be forever being drafted and never finished.  In the meantime you have a bewildering array of better-than-g options.  I do not think the one you are looking at is particularly sophisticated, for example it does not seem to use multiple aerials (MIMO) to increase wireless range.  I also think you would need new wireless adaptors to make use of the better-than-g capability.
With regard to better-than-g, unless you do a lot of internal transfers across your network I cannot see any great virtue in having a wireless link that is faster than your broadband.  For any sort of downloading (or uploading) your broadband speed will be the rate-limiting step unless your adaptor is operating at very low signal strengths.  If range is an issue then I can see a case for buying a multi-aerial router.
I would like to stress that I am not a technical expert on wireless, I'm just calling it as I see it.   

[#3]

Thanks Reed,  no ,distance is not a problem,I am replacing my present router because I am now getting continuously very low signal strength on both my PCs, although I have tried different channels it is the same on all. It's nearly 3 years old ,left on constantly(except holidays) and has given good service untill recently.