That router should reconnect if it disconnects - no need for user intervention...
Which firmware version are you on?
The latest is
Code:
NDLinkUK_DSL-G604T_fs_V1.00B02T02.UK.20041126
Kernel update is
Code:
NDLinkUK_DSL-G604T_kernel_V1.00B02T02.UK.20041126
Available as downloads from the D-Link (.co.uk) website
I recently updated mine to this firmware/kernel version and it seems far more stable now.
MAKE SURE you RTFM if/when you do this upgrade
Check your existing version by looking at this screen on your browser:
