I'm not a QoS guru but I'll build on Miguel's example as best as I can:
One thing I see is I don't see the two networks on your ethernet interface. (You may be adding a secondary IP later or something I guess).
Here are the ACLs to match on:
access-list 150 permit ip 192.168.x.x 0.0.255.255 any
access-list 151 permit ip 192.168.y.y 0.0.255.255 any
Here we classify the packets based on the ACLs above:
class-map match-all netxx
match access-group 150
class-map match-all netyy
match access-group 151
Here we allocate BW to each classification:
bandwidth percent 53
bandwidth percent 22
Note: The bandwidth (by default) can only = 75%. There is 25% reserved for link overhead. You can override this and use the bandwidth for your policy by using the max-reserved-bandwidth interface command.