Shot in the dark here but try these:
In your Network settings make sure TCP/IPv6 setting is unchecked but leave TCP/IPv4 checked.
Restart your router (I know most probably have).
In your Router's settings under security make sure Multicast is checked if you have that option.
Try a complete reset of your router.
Windows PC's check bonjour settings:
To enable, right click on My Computer and select Manage. Click on Services under Services and Applications. Right click Bonjour Service and select Properties. Change Startup type to Automatic. And, click Start under Service Status. Click Ok. Restart iTunes
Make sure if you have a firewall you don't have something apple related set to untrusted or blocked.
Check your ports for bonjour on a router:
https://discussions.apple.com/thread/2138901?start=0&tstart=0
In iTunes, click "Advanced". Turn OFF Home Sharing. Turn it back ON and it will ask for your iTunes password. Put that in and click "Done."
Try turning off wifi sync in iTunes for your iPhone and iPad, home sharing may now work.
Also check this thread:
https://discussions.apple.com/thread/3788964?start=0&tstart=0
Try assigning each device on the network a static IP.
I hope this helps.