Unbale to surf with internet explorer

Hi I hope someone can help.

I have just had a new computer system installed at work which consists of 7
Wyse terminals and a Cisco 1800 ADSL Router which is connected via a switch
to the Wyse terminals. The whole package has been provided by a single
company. The router has an IP Address of 10.187.83.254 and the workstations
have a Static Ip address of 10.187.83.x all with subnet masks of
255.255.255.0 this is a dedicated connection to the head office for the
people who installed the kit. But it does use the internet so assuming a
VPN is in place on the router. The company that installed the equipment
said we can put in a second line and run another ADSL modem of rhe switch
which we have done this is on 10.187.83.253 address when you open the
application that you use on the dedicated line it uses a 172.22.213.33
address. You can surf the internet but the routed application can then not
connect on the 172 address if you remove the defalt gateway from the Wyse
terminals Network config you can then use the app but not the internet can
someone please help??


Hope this all makes sense