Multiple networks on same switch

I actually do not have a reply for this question rather another question reguarding 2 networks same switch. Our company is in the preocess of updating an older analog phone system to function with an AT&T IPFLEX connection. We have come across a few challenges the current being having to push our network out to a remote building about 1000 meters from the server room. It has been proposed to run a fiber link to the site out of a supplied Avaya switch ERS 3549GT-PWR+ 48 10/100/1000. This will be configured as a VLAN and running as its own DHCP server to administer the IP addresses.

Now to the question. If I run a fiber OUT from the Avaya switch to the remote site and use the Netgear FS728TP at the remote site, can i run the fiber connection into the switch to support the IP phone system AND run out current network into the same switch??? Since I have to push the POE to the remote site I have to replace the current switch that is installed, so i am hoping for 1 single solution. Is this possible or am I missing something in the configuration??