Will Yosemite 10.10.2 support my HP printer and Net gear wifi

OS X- Printer and scanner software available for download

Printers not behaving? Reset them and start from scratch | MacIssues

There is no guarantee about non-Apple routers, but if it has worked in the past, then it should continue working. Visit D-Link and see if there have been any firmware updates for the router. If there have, then be sure to install them.

Go to HP site, support and put your model in and it will tell you.