Hello,
I've an extensive experience in building and managing critical high-traffic Web infrastructures (cf. my resume), I've already implemented those kind of protections (High performance distributed caching, Web application Firewalls, CDN ...) and I'm confident that we'll find a tailored solution for your actual issue.
Don't hesitate to contact me if you need more informations,
Alex
PS : 7 days seems to be a good duration as it's clearly not possible to perform a good analysis + implementation in 2 days !