I can’t find a driver for my HP…: Apple Support Communities. So Matt Broughton comes to the rescue.
The HPIJS open source drivers will support your printer. You can get the software on the OpenPrinting.org site. Unfortunately, that software only supports the printing function.
Amazon.com: iHOME IH-M1520B Optical Netbook Mouse, USB, Wired: Electronics. This ihome optical netbook mouse seems to be a very affordable and popular way to use a mouse. Supports major OS including the mac. I would buy it if I needed a mouse.