PA-450 and ATT BGW320-505

[MiamiDolphins]

Question,  I setup my PA-450 and ATT BGW320; however, I feel there is a loop as the connection sometimes drops or has slow connections on live connections like streaming TV and or live video.  I guess my questions are as followed below.

First, my setup is fiber going to the BGW320 that I could not get to change it to copper via ONT device as it will not work and not supported (I tired this anyways and it seems not to work)

(BGW320)<-->(PA-450 WAN Port)

(BGW320)<-->(SWITCH)<-->(PA-450 LAN Port)  I tried with VLANs but ATM removed them to get it to work and pull PUBLIC IP from BG320.

(SWITCH-->BGW320)

So, is this the best way to set it up without buying an extra wireliess router?  As is, DHCP is ran via the PA-450 and still using the BG320 for wireless clients. All clients is the PA-40 for DHCP.

PA-450 setup in L3 mode and all functions seem to work outside the seemingly loop?

Does anyone have this working, if so how did you wire the devices and anything I should be looking out for?

Thanks for any help...