How to configure Sipgate(incoming)-Voipdiscount (outgoing)

Hi there,
I know this question must have been asked a thousand times by many, but please forgive me as I am new and novice to the world of VOIP.

I have been using voipdiscount for nearly a year by keeping my laptop on for quite some time of the day, and also been using SIPGATE (.co.uk) for incoming calls for the same time.

I have now purchased a Linksys WRP 200, and have got rid of the wireless router Linksys WRT54GS. No idea if that is good or bad? But primarily for the sake of getting rid of the "keeping the laptop on all the time"-as it has damaged my machine's RAM.

Secondly I would also like to request if anyone could assist me configure the Linksys WRP200 voip telephone router for
Outgoing calls via VOIPDISCOUNT
Incoming calls via SIPGATE

by enabling me use only one single phone set.

Please could anyone assist, kindly.
Many thanks in advance.
Regards