The router interface address will be a useable ip in the subnet range, normally you use the first or last ip in that subnet but its your choice
So in your example you are using a /26 mask (255.255.255.192)
This gives you subnet block sizes of 64 eg multiples of 64:
192.168.1.0 - 192.168.1.63
192.168.1.64 - 192.168.1.127
192.168.1.128 - 192.168.1.191
.....and so on.
Using the first subnet 192.168.1.0:
Network address is 192.168.1.0
Broadcast address is 192.168.1.63
Useable IP's: 192.168.1.1 - 192.168.1.62
The router Interface address could be any IP in the useable range .1 - .62 but I would use .1 or .62 being the first and last addresses.
Hope that helps