So I got this message a few days ago 

"We're a little embarrased to say this, but it looks like some of the hardware being used to host your servers became overloaded"

This promted me to move servers from one region C to Region B and A, now I am getting the same message stating B is having the same issue. 

Is there any plans for getting new equipment?

When a server near capacity, individuals are informed of the server being at/near capacity. Though, in this case, it's the whole NA region. When this happens, each server impacted is informed of the server being at/near capacity as they approach such capacity.

Usually, large clusters get these notifications first, and are impacted much more easily / readily. Those clusters generally aren't able to move to other machines, since clusters take up far more resources and space.

As I'm just a volunteer, I can't see the complete usage system of the whole host.

My recommendation, if you're hosting a large cluster, would be to submit an email to support. Best case scenario, they can give you a time table if the whole NA region is at capacity. Though this doesn't appear to be the case, as I have a server on each sub-region in NA. None of my servers in sub-regions A, B, and C are reporting a capacity message. Since that's the case, you most likely are looking at some lesser case scenarios:

1) Since these are shared hosting VMachines on baremetal servers, all of the virtual servers on the baremetal server you're on have received the same message. Those individual servers / smaller clusters will be able to move to an NA machine with available space. Once they do so, the message will go away.

2) Overtime, the rest of the NA services will also hit capacity. At that time, as has occurred in the past, the host will order more hardware to be installed at the Data Centers most impacted. At present, that appears to be Data Center C, based upon the sparse information I can gather.

3) It's a possibility, and take this with a grain of salt as I'm an non-affiliated helper, that sending an email to support will have support come up with a creative solution not listed above. Though, with possible costs and T.O.S. with this host considered, I'm not sure what all that would entail.

tl;dr - As ARK popularity spikes, this host adds servers as fast as financially possible to meet demand.