On my last day my co-worker told me this. I'm not sure what バネに means. I tried looking it up but didn't get anywhere.
ここでの悔しさをバネに、次のとこでもがんばってくださいね
It's an omission from バネにして, and the sentence means "Make your regret you felt here into a spring and do your best in the next place as well".