Multiple Site to Site VPN’s

I have a client that has a branch office located in another state. Right now we have a site to site vpn between them where data is shared and up tp 1.5 GB of data is sync between server them nightly. Both DSL connection on either side is 6 Mps down and 768k down.

We are planning to add another branch office in another state with the same setup. We will do aother site to site VPN between it. Do you think since we should bring in another DSL connection in the Corp office to support the addtional VPN? We are planning to upgrade to business cable of 10m down and 2m up. But this may not be enough.