PfSense with Via Artigo box?
I've installed pfSense on Via Artigo embedded computer, which has only one NIC which I am using for LAN connection (vr0), can I via VLAN have another "virtual" NIC which will be used for Internet connection?
I don't have manageable switch..
You probably need a VLAN capable switch so you can have a "non-VLAN" connection to your internet modem.
pfSense supports some USB ethernet interfaces so that might be an alternative way of getting a WAN port. However for not much more than the price of 100Mbps capable USB NIC you can probably get a small VLAN capable switch (e.g. Mikrotik RB250GS)