Advice on ipod touch fast!

I have an ipod touch and I have some songs on it that I like. my cousin gave it to me and there her songs from her computer. I want to keep those songs and import more songs from my computer to my ipod
is that possible
can I import songs from my ipod...

to my computer then transfer it back with my songs from my computer and the one I transtere from the ipod to the computer
ny the what I have a pc.

Ok here is what you can do
turn on itunes and go to the sync tab. change the settings to sync manually. This will prevent your ipod from deleting the stuff that's already on there. then drag and drop the new songs to your ipod from itunes. If your ipod starts to sync before you set it to sync manually, you will hear it chirp and start to sync. you can slide the slider bar to cancel the sync.

it will chirp when you sync manually too, so as long as the settings are correct you don't have to worry about the chirping.

absolutely yes,you can make it and all you need is a three party utility which I recommend Aniosoft ibackup. It enables you to transfer iPod's music and other content to any storage device and iTunes as well. And both the backup in the storage device can be convered and restored with no any change and no any risk.And the data in the iTunes is quite in accord with the iPod's data including its playlists,rating and etc.
So in your case,you can make a music transfer from her iPod to the iTunes in your computer with this tool and also make a backup for the ipod's content in your computer as well. Then the iTunes in your computer includes both her songs and your songs(your former songs) and what you need to do is syncing the iTunes to your iPod.
There is a note that needs your attention,you have to turn off the auto sync of the newly installed iTunes before you can make this transfer.
for your convenience,I'll add the links here:
http://www.aniosoft.com
good luck to you.