See the two top answers to the question "Windows program to limit bandwidth of other programs?"..
I use NetBalancer. While its a paid software, a free version exists, but can restrict traffic on upto 5 processes at a time.
I use Net Limiter, which is free.
NetLimiter is an ultimate internet traffic control and monitoring tool designed for Windows. You can use NetLimiter to set download/upload transfer rate limits for applications or even single connection and monitor their internet traffic.
Along with this unique feature, Netlimiter offers comprehensive set of internet statistical tools. It includes real-time traffic measurement and long-term per-application internet traffic statistics
At the very least it seems that NetLimiter will allow you to limit the amount of data per network adapter, though I cannot personally vouch that it supports an automatic change to another adapter.