When I download the dlcs I can play them only if im connected to live, how do i get to play them if I am not connected to live?

You would need to be playing on the system that they were originally downloaded to. The License is tied to both the system and user that downloads them and on the original system it was downloaded to any user can play them in offline mode (but if say you have had it repaired and you no longer have the original system (they usually swap the system when repairing with another refurbished system and then refurb your unit later) - you will then only have access if Online with the user account they were purchased on -- IIRC they have updated the procedure so that you can now reregister the repaired system as the original system by migrating the license in order to restore the ability to play offline.)

How do I do this?

http://www.xbox.com/en-US/Support/LicenseMigration/Home

Many Thanks

Sorry to bring this up, but is there any way to do this withoout a router? e.g. can I somehow download it the update thing even though i only have one modem?

I appreciate the help.