Why don't you put it on a external hard drive and sync across?
If not...
Don't forget to authorize the new computer as well. Launch iTunes and go to Store>Authorize this Computer.
This is the original thread.
https://discussions.apple.com/message/11527201#11527201 1) Without connecting your iPad to your laptop, start iTunes. Click on Edit. Click on Preferences. Click on Devices. Check the box next to "Prevent your iPod etc. from automatically syncing." Click OK.
2) Now connect your iPad to your laptop and start iTunes.
3) When iTunes starts, right click on your iPad under Devices in the left column. Select Transfer purchases etc.
4) After it finishes transferring all your apps to your new laptop, right click on your iPad and select Backup your iPad.
5) After it finishes backing up your iPad, right click on your iPad and select Restore etc.
6) After it finishes restoring, left click on your iPad , then click on the Apps tab on top, and check the box next to Sync Apps, then click on Apply below.
If everything on your iPad looks good after the sync, go back and click on Edit / Preferences / Devices and UN-check the box next to Prevent your iPod etc. The only other thing you may want to check is if your contacts, bookmarks, etc. are syncing correctly now. If not, go to the Info tab after connecting and make sure you indicate which features you want to sync with what sources.
Make sure that you move your iTunes library from the old computer to the new one as well for all of your music.
Here is an article that can help you with that.
http://support.apple.com/kb/HT4527