When answering the question about "Why are you looking to leave your current job?" a simple answer in your case that informs you are looking for a new opportunity and to expand your skill set could be enough. You don't need to walk in going "I hate my job, it's horrible, I want out." You've simply been there awhile, don't feel your position is going the right direction, and are looking for a new opportunity.

I'd say it's ok to add some flair to your job, but not to lie. Don't say you know how to run a program that you've never used and have no idea how to even use. But do find creative ways to say the same thing. In interviews I'll mention using certain programs, not because I'm a pro in them, not because I will ever use them in a new job, but because it shows I am willing and able to learn new things. You can tailor your creative answers to also meet the job description, in one interview I may play up my ability to write a press release since the job calls for it, in the next interview I may tell them how much I love making graphics. Just be honest because you need to be able to do the job once you get offered the position.