Cisco Firewall :: ASA 5505 - Create ACE For Range Of IP Addresses

trying to configure our ASA 5505 (hence my request for the ASDM). However, I can go CLI if push comes to shove.
 
What I'm trying to do is allow a range of IP addresses on the inside interface (those which the DHCP server is doling out IPs which are XXX.X.XXX.14-140) to access email only (which is hosted offsite). They still need to access the file servers which are on the inside but nothing should be going out to the internet other than email.
 
I believe I have to create a Network Object which contains the IP range I wish to restrict. I can see where I add the Network Object but I don't know what the syntax should be to specify the address range.
 
I'm also not sure what the sequence of the ACLs should be and whether or not I can keep the default Access Rules in place. There are the two implicit rules: 1) Permit any traffic out to less secure networks  2) Deny any traffic to anywhere (which is superceded by rule 1, yes?)
 
To create an Access Rule like the one I desire, do I need to move the two existing rules down the list so that the new one will supercede both implicit rules?