Windows 7: Help with creating a home network please!

Thanks for reading! Any help greatly appreciated

I'm not too familiar with the tech terms, so I hope I will make sense when explaining what I want to do...

Ok, I have the following devices at home: desktop PC, notebook, PS3, media player. I also have 2 DSL lines and two modem/routers.

Currently I have the desktop PC connected to DSL line 1 (modem 1), and the other devices connected (some wirelessly, some not) to DSL line 2 (modem 2).

What I want to do is create a home network that allows me to transfer files easily between the desktop PC and everything else. As far as I know, the easiest way to do that is to connect the PC to modem 2 as well (the PC has 2 Ethernet ports) - however that's where I run into problems.

Is there some way for me to set it up so that the PC only receives internet access from modem 1, and LAN access (but not internet) from modem 2, while it's connected to both modems? (The reason is that I want the PC to have dedicated bandwith from the first modem, without sharing it with any of the other devices, and have everything else connect to the internet through the second modem)

Hope I'm making sense

Thanks!