Router and Modem replacement, need help!

[Jedimushroom]

So I've decided to ditch whatever god-awful router/modem came with my 20mb O2 connection, as it crashes horribly and drops my connection.

I think I would rather go for a separate router and modem combination this time, but the world of internet connections is murky and confusing, and I really need the help of some kind internet fellows.

I need wireless connection, not for myself but for other users in the house. At the same time I need a high speed wired connection for gaming, and a durable network that won't drop connection. If I want wireless do I just need a wireless router or a wireless modem too?

I was thinking of buying the D-Link DIR-655 router but am not sure what modem to get with it or whether there is a better router around.

I also want to know how easy it will be for me to change my current router/modem to the new combination, and how I would go about it.

I really need help here, as I am totally out of my depth when it comes to internet gateways, so many numbers that mean nothing, and firmware... all the firmware...

Thanks in advance for the help!