It looks to me like you may need to approach her about her own availability, but also work on your own communication techniques.
Your initial post was a little confusing, poorly formatted, and needlessly verbose. There exists a chance that your manager finds your emails confusing, and has simply started ignoring them. That would not be professional of her, but it might be understandable, especially as she's non-tehnical.
I believe you may also have some misconceptions about how you might go about requesting information, and most importantly from whom. There are steps you can take to improve the situation.
First of all, she seems to be a very busy person, and perhaps going to her with your questions is not the best approach. Find out if there's someone else who could give you the same information who might be a little more accessible.
Second, you seem to simply walk to up her office and expect that she make time for you, which is not a good assumption (as you've found to be the case). Instead, maybe ask for a quick meeting, and only go up when she replies in the affirmative.
If I were you I would make it my number one priority to set up a 1 on 1 meeting with her next week. Come to that meeting with a sample status email you've sent her, as well as a notepad.
Explain that you'd like to know how you might adapt your communication style such that she will find your status emails useful. Ask her to look at the status email with you, and tell you which sort of information she finds useful, and which she does not. Make a note of that.
Inquire whether she feels your emails are easy to read, or if there's something you could do to improve them. Maybe she'd prefer short, point form lists. Maybe there's technical aspects that she doesn't want to know about. Heck, maybe ask a coworker to proof-read them before you send them. Also ask her how often she would like to receive those emails.
Then go into how you sometimes need to get a hold of her for clarification of certain project details, and how you desperately need a clear line of communication (IM, email, etc.) such that you'll always be able to get a hold of her. Ask her whether it's reasonable to expect to get a hold of her the same day, or whether she'd prefer you to set up meetings several days in advance.
Perhaps she could also point you to some other resource whom you might pass your questions to. However, the problem here is not simply her becoming more accessible to you. You also have to improve your style of communication.
Don't waste her time walking up to her several times a day with a small question each time. Instead, do as much as you can without her input, compile a list of questions, and only approach her once.
You'll also have to keep in mind that since she's non-technical you must ensure that you adapt your communication style to her level of understanding. Use analogies, or simplify the problem such that you get the necessary guidance without making her feel like she's wasting her time listening to you.