Look on E-Bay for enclosures. Mine was a brand-new Hoffman 24"x24"x12" heavy gauge steel NEMA enclosure I got on E-Bay for $99!
You should allow for airflow, but for such a small supply, I very much doubt forced ventilation is required.
If the bolt mounting the power transformer is in any way connected to anything electrically, then it was horribly mis-applied. The transformer should have a rubber insulator top and bottom completely isolating it from the bolt and "washer".
Regards,
Ray L.