Hello Rachel_G,
Thank you for posting all that info, we should be able to get this working for you in no time :)
1. Reset the printing system: http://support.apple.com/kb/ht1341?viewlocale=en_us&locale=en_us
2. Download the latest 10.9 software for you printer: Software and Drivers
3. Re-install the printer by running the download from step 2. Continue through the steps, it should see the wireless connection.
4. When it gets to the "add a printer" configuration section, try using the HP driver instead of Airprint. (click the plus sign > add printers and scanners > Envy 4500 Bonjour > Use: HP Envy series > Add
5. Finish installation, reboot the mac, and try printing again :)