qos configuration help example

I have a RB750 connected to internet on eth1
total bandwidth for this connection is 2MB-rx 256Kb-tx

eth2 is connected to LAN (10.10.10.254/24)

eth1 as a public IP address
eth2 as private IP address

I need to give priority and reserve bandwidth (66kbps) when is present traffic to the following IP:
78.141.179.70
216.218.147.163

When traffic to those addresses is not present all band should be usable by users on lan with equal distribution.

Can someone provide a configuration ?

Regards
Tom.