That depends on what's broken. All you can do yourself:
- get the drive out and put it in again (works if it's a loose connection)
- get the drive out and connect it via a powered USB to SATA/IDE cable (works if the enclosure is broken)

If none of the 2 work, it's time find a professional data recovery company, because they will have to take the drive apart to salvage your data.

I hope you're lucky enough that somebody told you that external hard drives aren't storage. So you don't lose any data if you can't afford data recovery and just buy a new drive, because you have a backup copy somewhere else.

Kees