Greetings everyone. I need some specific information about Russian visas if anyone happens to have any insights whatsoever from a Russian perspective, a Canadian perspective or whatnot. I am seeking information from various other sources as well (inviting organization in Russia, Russian visa application centre in Canada, as well as a visa services company that I have used in the past for obtaining a Russian tourist visa. I am sorry for this shotgun approach but, to be honest, I am in a little bit of a panic mode right now, so I want to gather any and all useful information as quickly as possible.
I will be travelling to Moscow as I felt it was time to get better acquainted with Abashka, seeing as how we are so fond of each other (Abashka, before you respond, please understand that I am joking, just trying to lighten things up a bit).

Actually, I am going to Moscow to attend a course with the intention to begin working for the organization offering the course following the successful completion. I have been told that I have two options in this situation: a work visa or a business visa.
An added wrinkle to this is that I need to leave Canada by December 27 at the very latest, due to a prior engagement in Europe prior to entering Russia. I understand that I must apply for my visa in Canada (my country of nationality).
The organization has told me today that it they can get the invitation for my work visa by December 11 and then courier it to me which would take another 3 business days. Given that I will need to courier my documents to a Russian consulate here and also taking into consideration the holiday period over Christmas, I see no prospect for getting a work visa in time.
The inviting organization has told me that they can arrange the invitation for a business visa within 10 working days. So this is a little quicker and may leave me with enough time to get my visa. However, what is unclear to me is whether a single entry business visa would require me to submit an HIV/AIDS test (this is required for the work visa). They also stated that upon the expiry of my business visa, I would need to leave the country to reapply (presumably for a work visa?). Would I have to come all the way back to Canada (my country of nationality)?
I am just wondering if anyone has any ideas of what I can do right now to ensure that I will be able to legally enter Russia in early January, keeping in mind that I must leave Canada by December 27th for a prior engagement which I cannot cancel nor postpone.
Again, I apologize for this, but will appreciate any thoughts or advice from anyone. I am in a little bit of a desperate panic mode at the moment as it has dawned on my that this is all suddenly getting very very late.