Dlink 624 and 604 Bridge

Hi,

I have a cable network internet connection which I get wirelessly but the
signal is very low and my printer is nowhere near this router (624 - cable
router).

I have purchased an ADSL router (in the hope that I can get this connected
to the same wireless network but nearer my printer so I can connect my print
server and increase my signal from the cable router.

Why buy 2 different types of router? This is for future proofing should I
wish to change to a phoneline internet provider, however, I cannot seem to
find in their documentation how I can bridge these 2 routers together and
use the adsl (604) router as, what would be known in old days, a hub.

Can anyone advise how to do this with these bits of kit please?

FYI the adsl unit is the DLink DWL-G604T and the cable router is DLink
DI-624.

Many thanks for advise/help
Stu