what can we do about the unhealthy heat in our apartment that we pay the landlord for?...?

the heat and water is supposed to be included, but it actualy is $150 a month even in the warmer wheather...we live in michigan...the building has 6 units and it has a steam radiator system with the boiler in the basement...sometimes it is over 90 degrees in our place...it was 18 below zero the other day and we had to open all the windows to our place and it still only brought the temperature in here to 79...sometimes the radiators go completely off...they went off about 15 hours ago and now it is 51 degrees in here with the windows closed right not of course...the landlord does nothing to fix the problem...our daughter has had 2 ear and througt infections this winter and has never had them before...when it is hot in here it gets so bad that it melts the chocolate in our cupboards...i went down to the basement to take a look at the boiler steam system...there was paperwork on the wall...the 2 yr inspection for it is 4 months late, and sheet that showed service calls said the last one was back in 2000!...so they haven't even had any "tune ups" on this boiler for 9 years!...wow!!!...i am not going to mess with the boiler because that is beyond my knowledge and i also don't want to get blamed for "breaking" it...what can i do about this?...can i turn the landlord in?...where would i do it?...how can i get him to fix it?...oh, we do not have a thermostat in our apartment and there are no controlers on the radiators so we are stuck with what comes through...also, we don't have screens on our windows or doors...we are forced to open them when it is 90 degrees in here...we had a squirel that got into our bedroom and destroyed a food basket gift we had wrapped...we asked the landlord if we were forced to open our windows and doors if he could at least put screens on them so that we do not get anymore possible rabid rodents and wild animals coming into our place and destroying our belongings...is there anyway we can get him to put screens on?...any help or advice would be greatly appreciated...thank you!!!...
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The first step to obtaining repairs is to notify the landlord in writing, preferably sent via Certified Mail return receipt requested, so that you have proof of the request. If the landlord does not take care of the problem, your next step is to call the local housing inspector, who will force repairs and/or fine the landlord.
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