I went to a liberal arts college and my communications major also did not have a lot of business classes. I actually ended up minoring in business to add that in.
That said, I wouldn't stress too much about your major. It is important of course, but I think as students we tend to over emphasize the importance of it. The reality is, you learn most what you will do in your career by working on the job and from your managers and mentors, not in school. The purpose of school is to teach you how to think, analyze, and relate, more than anything else.
And if you are worried about the perception of future employers, I think it is very common for communication majors to end up in the marketing field. I actually think I got more out of my comm classes than my business classes when it comes to understanding how to think critically, speak well, and write... the skills I use on a daily basis in my career.
I would suggest studying what you enjoy learning and the rest will come.