thank you guys for you replies, I managed to solve the problem and configure the router following the info from here:
http://wiki.mikrotik.com/wiki/Manual:Si ... ultihoming
In my case i have one provider for internet connection, from the second one i have only the public IP class routed on the provider public IP. The problem was the route not advertised in BGP.
In order to solve this i configured the WAN (interface 1), LAN (interface 2), DNS and GW on the mikrotik, after that i added the following:
#set our AS number
/routing bgp instance
set default as=30
#add BGP peers
/routing bgp peer
add name=ISP1 remote-address=82.75.x.y remote-as=10
/routing bgp network
add network=193.230.y.y/24 synchronize=no
/routing bgp peer
set isp1 in-filter=isp1-in out-filter=isp1-out
/routing filter
#accept our networks
add chain=isp1-out prefix=193.230.y.y/24 action=accept
Now all is working fine, from internet i can contact the public Ip class and vice versa.