It depends on your setup, and how you get that pool of IP addresses.
Is your subnet routed to you, or does it only exist on the WAN of your router? If it’s routed, it’s just a matter of assigning the subnet and the pool of public IP addresses to the LAN of your router.
If it’s only on the WAN, thing get sticky and ugly. You’ll need to contact your ISP and see if you turning on proxy-arp on your WAN will mess things up for them. If not, there is a proxy-arp hack that you can do to accomplish this.
I think this is the thread that describes how to do it:
http://forum.mikrotik.com/t/public-ips-for-client-not-bridging/34246/1