Help Needed

So here's the thing,

i was running out of space on my mac so stupidly i erased my itunes folder as all my music is on my ipod, obviously i freakin erased all my ipod touch apps and since i wasn't aware that they'd all gonne i bought another app, now i can't sinc that app because herr itunes says it'll erase all the apps on my ipt, and only leave the new one from what i've understood...
so all i want is to put the new app on my ipod touch without erasing the tonnes of others i have, and i would like to not have to buy the same app directly on my ipt

i now this is my dumbass fault...but considering i haven't jailbroken the damn thing i hope that apple (or somebody in the forum that pittys us fools)has thought about the dumb paying costumer and there is a way out of this...

thanks for your help

 

i had a backup of the apps, and have put them back in the right folder of itunes, but still it doesn't either recognize them on itunes nor allow me to sinc my ipod touch without loosing the apps i have on it...