I have always thought that coming to someone with just a couple days to do something that you don't know how to do and assuming that it is simple and easy and can be done in a couple days is just about the most insulting thing you can do professionally.
I assume you wouldn't mean any insult by it but leaving something that you can't do til the last minute and assuming it is simple is well... think back to a time ( assuming you have been through this ) where your non-coding boss came to you with a 'simple request' that had to be done 'right away to complete a deal' which wasn't actually simple at all. It might appear simple to someone without any knowledge of the problem domain but you as 'the expert' know that isn't the case.
Perhaps you have already talked to a graphic designer who gave you a general timeline for what you want and I'm totally off base, but it doesn't sound like you have.