1 - based on the tagline, the picture of the guy managing a server, and the 4 features you highlight, it's still really unclear what your software does, who the target audience is, and what problem your software solves.
2 - your HN comment above does a better job of describing what you do but it's not communicated on your site. the sentence about "all these people need to..." is what your homepage should address head-on, instead of the various technical tag lines you have on the homepage right now
3 - re: struggling to get the first customer - just wondering how you came up w this idea and how you've iterated thus far if you don't have customers or users. when you say maintenance people really like it... what does that mean?
4 - re: maintenance people - are you talking to the individual maintenance man, the guy that is actually in the field doing the HVAC repairs, or are you talking to the operations manager that sends out work orders? i hope you're talking to the operations manager/facilities manager and not the blue collar worker, since the former is your customer and the person who is going to give you money.
5 - as for adwords - if you are bidding on the super generic term "CMMS", that would explain why you are getting a $4 bid rate. but, i also suspect that your "quality score" is fairly low and that also plays a huge role on your avg cpc.
6 - if i were you, i'd focus on on-page factors first, especially better communicating your value prop to your identified target audience. once you do that, then go out and find niche forums that facility managers, hvac professionls, and the like hang out. get in the mix and start conversations and ask them to use your software. once you have a few people actually using this thing and they are integrating it into their workflow, you'll have a better shot of converting these guys into actual paying customers OR pivoting to something else OR iterating to create better tools.