A gateway is just another host on the subnet. While there are conventions as to what your gateway "should" be, there's nothing that says it has to be there.
That said, a /30 isn't exactly useful--it's the smallest tcp/ip network possible with enough address space for a network address, a broadcast address, and two hosts. Since you're already apparently using 63.149.131.58, any router on the network would have to reside at 63.149.131.57 (.56 being your network address, .59 being the broadcast address.)