Well, I know nothing at all about your company of your business, so I don't have any meaningful suggestions as to "a) fixing your business".
As for b) "getting off this cursed server" my advice is to make a business decision on how quickly you want that to happen, and to what lengths you want to go do accomplish that.
If you need to "get off the server" you are on now (or as quickly as possible) I suggest obtaining a new hosting account somewhere, uploading you site to it, and changing the DNS entries for your domain to point to it. That won't necessarily get your site or email up as fast as some other alternatives, but it will get you off the server right away.
If you want to do much of anything else, you are going to have to deal with DreamHost tech support, as they will have to be the ones to get your sorted. IF they can do that, you have a chance of being back online faster than changing servers, but there is no guarantee of that.
Is both your POP3/IMAP EMAIL access via external client and your webmail broken? Have you ever received email at your Dreamhost account?
If you have other email accounts that are functioning (separate from your broken DH accounts), and if your domain is properly set up with DreamHost's DNS and that is working, you could simply forward all your email to those other email account (set up forwarding in the panel -> Email -> Manage Email screens) so that you can at least get email sent to you at your domain as a temporary workaround.
Other than that, since you haven't shared your domain name (is it reachable at all?), or any other particulars of your situation ( can you reach the email server?), or what tech support has told you, so I don't know what else to suggest.