Cant sync my ipod without loosing all my apps

Hello,
I bought a second hand ipod touch recently from ebay. when i plug it in to my itunes it will only let it sync with my computer which means i will loose all of the apps(there are only apps on this ipod, no music). I cant athorise the computer because I dont know the person who previously owned the ipod so dont have his log in details. Is there any way that i can keep my apps while syncing my own music ect?