cisco 3550 intervlan routing

Here is configuration guide for doing that from Cisco's site:

http://www.cisco.com/c/en/us/support/docs/lan-switching/inter-vlan-routing/41260-189.html

You need to use VLAN's no matter what.  If both subnets/VLAN's need to be on the same interface of the firewall and 3350, then on the 3550 you need to configure the interface as a trunk with at least one of the VLAN's being tagged.

On the firewall you need to configure the interface so that both VLAN's are active on the interface and at least one of them needs to be tagged.

so i can make 2 vlans - 192.168.45.x and 192.168.0.x thats fine

Now the conenction between the switch and the sonicwall, what ip's should i use there?

How is the sonicwall connected to your network right now?

WAN --> Sonicwall

Not sure what you are asking here.

So the Sonicwall is just connected to your WAN?  No LAN connections?  If there is only a WAN, what are you using it for?

Also, does the Sonicwall need to have an IP address on the 192.168.0.x subnet (I am assuming that is is 192.168.0.0/24).

Of course there is a LAN, i said this is a DMZ interface im working on. Yes the sonicwall is the gateway for the DMZ so of course it needs an IP.

How is the sonicwall connected to your network right now?   Meaning , a managed switch or non-managed switch.

Do you plan to replace the current switch with the 3350, or are you just sticking the 3350 in-between the Sonicwall and the current switch.

there is just one device connected directly to the sonicwall on that interface. No switch.