MT Router with DSL & Tomato Router in Client Mode Question

Hello,
Hoping someone here can lead me in the right direction with a specific project.
I have an RB2011UAS-2HnD (v6.0rc6). It’s gateway is 192.168.1.1. I am connected to the internet via pppoe clent through ether1.
I have a Tomato Router that is in Client Mode connecting to my Hotspot created by my mobile device. Connecting a computer to the Tomato router gives me an internet connection , albiet quite slow but usable for non-bandwidth intensive browsing. Inevitably, I’d like to connect the Tomato router to my MT router so that it can act as a back-up connection in the event my pppoe connection is down.
MT Router: 192.168.1.1 DHCP 192.168.1.5-192.168.1.250
Tomato Router: 102.168.2.1 DHCP 192.168.2.5-192.168.2.250

'What is the best way to approach this?

Thank you!

Like this?
http://wiki.mikrotik.com/wiki/Manual:Simple_BGP_Multihoming

Not Excactly…I don’t think. Can I use BGP to connect to a Tomato Router?

My RB2011 router connects via DSL and receives a dynamic IP.

I’d like to connect my Tomato Router via ethernet to my RB2011 and utilize the wireless client mode so that when I am in the house, I can turn wireless tethering on on my cellphone, giving the tomato router an “Internet Connection”.

Thank you!