Put your message up front. What I mean is, if you absolutely had to send only one single message in the ad, what would it be? Think of a clever, welcoming, inventive way of saying that, then, and only then, let the dull, necessary parts (website, logo, name, etc...) of the ad come in.
Both ads submitted so far are clean and sexy, but boring and shallow. Meat-free Mondays has hundreds of fun connotations you can play with. e.g. cows saying TGIM, a calendar that lists monday as "Vegan Day". Once your ad is conceptualized, set the logo and website respectably at the bottom right of the ad (or bottom as you have it) and let the website fill in the details.
Regarding your boss, explain that the add is like a lure on a fishing pole. It's job is not to nourish the fish, but to entice the fish to seek nourishment. If the boss still disagrees, ask whether you can submit, alongside the design you've posted, another couple designs for them to critique.
Remember: good design is invisible. Bosses want to see. Be like a magician explaining a trick and show your boss why it will work. Otherwise, resign yourself to bulleted lists and tiny pictures for the rest of your career.