Office Internet

We have recently installed cicso routers to our office and other remote sites across australia, however our internet and email is not working correctly at our main office, very slow, email is bad, coming in is ok, but to send within our network, they never seem to leave and just sit there. I know for a fact its not the internet and has something to do with this VPN we rolled out. Our IT says many things, from virsus, PC's need replacing, OS is corrupted and so on in which is not true. Also the clock on one of our servers keep going back 1 hour, you add 1 hour and goes back within 30 minutes, even i put if 2 hours ahead and it goes back 2 hours after sometime. The settings are correct, time zone and DLS is ticked.

I have pinged a number of random sites as sometime i get timed out and other sites give out anywhere from 40ms - 302ms.

Any assistance is much appreciated.