I need about 20-25 Ethernet connections so I guess a switch is the only way to go. My question is does a wireless access point create a new network (would it make the wireless network a separate network?). I want one network for wireless and wired devices.
@user1090389, why don't you try having a simple SOHO router handle your DHCP requirements like RobM suggested above. If it's a relatively simple network structure, this is a quick and inexpensive solution that can work. I use it on one of my subnets to issue ip addresses out to about 25 pc's. It doesn't give you the most control but it works for what we needed and it's really simple to define a range of addresses to assign. If you do need more control, than a server based solution would make more sense.
Not necessarily... Typically, a true wireless access point is just a bridge to your existing network.
In your situation, how do you allocate IP addresses? Is there a DHCP server? You could assign the switch port that the access point is connected to a specific vlan and assign addresses for wireless devices a different IP scheme... but the details of this depend on your topology.
A wireless access point is simply a bridge between two physical kinds of network: Wired and Wireless. It's a logical point to seperate networks should you want to do so, but you don't have to if you do not want to.
So you should be fine, the configuration you want should pretty much be the 'out of the box' configuration for your gear.