How can I reafix the sprayer arm?

Not good news for you:
The only time I had a spraying arm drop was because it's metal was worn through.
If that's your case, the only solution is to find a replacement.
Look on the maker's web site or a retailer if you can get a replacement.
You may also look for amy local repair shop or used home apliances store. They may have it in stock.
You may also take your chance on e-Bay or some other place.
With some luck, a piece for an other model or brand can be just suficiently similar to work.

Electro
May 2013