The specs are intel core 2 duo (32bit),2GB ram,NVIDIA GeForce 9600 GT,260GB HDD i think and i don’t remember what mobo xD. I don’t know how to use it yet but i want to use it as router, firewall and put vpn
yeah. you don't need that gpu.
Is already there there xD
The only problem may be NICs and compatibility. Intel is pretty much guaranteed to work. You would normally also need at least two NICs.
NIC is expensive?
Yes. As mentioned by @anon5205053 "you don't need the gpu" and after installation a terminal/monitor, as it has an excellent web interface. I'd also recommend ipCop as lightweight, but very capable/reliable firewall that also supports VPN for those with more limited resources than yours.
I haven't had an comparability problems with non Intel nics in pfsense. You might have to disable TCP offload but I've used a be charged of $8 tp-link nics before I got some Intel ones and there really isn't much of a difference. But you can get dual port Intel ones on ebay for around $30 so you might as well just get one.