hole in intercooler, can it be welded?

If it cracked once, it'll crack again.

To fix it, there may be a chance that the tubes get welded shut too...

Upgrade to something better.

I've had good luck jb weld and with cleaning the surrounding area with a demeL. Make sure you use a stainless steel wire wheel on aluminum. sealed up 3 bars leaking at the end tank. Going strong for over a year. I couldn't get a local radiator repair shop to touch it.