Redundancy Question??!!

[Spoutnik]

Hi guys, We recently add new telecommunication link between Quebec and Montreal. We now have one lan extension 100MB(primary link) and a ADSL backup link. I have two routers (Cisco 2651 for the 100Mb link and Cisco 1605 for the ADSL link) configured HSRP and EIGRP with virtual interface for default gateway in montreal and both talk to a Cisco 2621 in Quebec. It works well but the response time in case of failure of the 2651(principal link) is too long(about 20 seconds to know that the master router is down and to updates dynamics EIGRP routes) to step to the ADSL link. I tought about LAG (802.1ad) but my link aren't at the same speed so it can work properly Is it a better way to configure redanduncy between two routers and give me a acceptable response time (one or two seconds max)???? Thanks for your help! Spoutnik