Linux sys admin - URGENT

We run an extremely popular file hosting site (over 150,000 uniques per day). We recently relaunched with a new download system but our servers are being overloaded with too many HTTP requests, as we are serving out downloads through Apache, in order to limit simultaneous downloads to one IP address, and to restrict the download speed. Unfortunately our sys admin does not have much experience in this field, therefore we are looking for someone who can URGENTLY optimize our 16 download servers. Experience in high traffic servers is a must, along with extensive knowledge of Apache, Linux and PHP. We need someone who can deal with this TODAY as currently our site is unusable. Please include your contact phone number in your bid so we may reach you. Prefer to work with a US based supplier.