Very cool--you're on a roll! The teal Model 1205s were manufactured and sold from 1968-1974 (there was also the later gold Model 1205s which were named "Jubilee" and nicknamed "Golden J" for Electrolux Corporation's 50th Jubilee in 1974).
I agree that for $10 you can't complain about it being dirty. It will likely clean up nicely with some elbow grease and a disinfectant such as Pine-Sol or Mr. Clean. Then you can put a protective finish such as furniture polish on it which will give it some extra luster.
Your hose is the original--or at least it bears the original colors. It, too, can be cleaned with a cloth dampened in disinfectant. Instead of purchasing a new one you may be able to repair it using the directions from this thread (if it isn't too worn). Otherwise you can keep it for display:
http://www.vacuumland.org/cgi-bin/TD/TD-VIEWTHREAD.cgi?22656
I haven't actually done this yet but am planning to at some point.
The Model PN-1 power nozzle makes me think your cleaner is pre-1972 (when the polished aluminum-hooded Model PN-2s were introduced). I'm not sure about the noise you're hearing. My first thought is to take out the brush roll, clean out any threads, hairs, or other debris from the bristles and pins; check to be sure the belt is in good shape; reassemble it and see if that takes care of the problem. If the brush isn't spinning afterward push the circuit breaker to reactivate it. In the event that the motor is bad there are occasionally replacements online, or you can check with a vacuum store to see if they have any old stock (particularly Aerus franchises). Be sure to ensure that both the elbow and hose are clear of any obstructions, too.
While you're disinfecting take some time to clean the power cords. Allow them to dry before coiling them. The 1205's will benefit from sprinkling some talcum powder on it which acts as a dry lubricant.
See aerusvacuums.com for contact information to request electronic copies of the owners manuals, to order bags, etc. if you don't have an Aerus franchise close to you.
Post photos of your machines once you've cleaned and polished them. Best wishes.