I think you've got it narrowed down to the two routers I'd suggest.
Those two are what we have running here.
As far as your current router, what they are having you do is reboot
it. There are various levels of rebooting and some do a better job of
clearing out the memory, as I understand it.
You should be able to find the 1.0 firmware somewhere on the web, I'd
think. Where's the D-link forums? Somebody can pass it to you...