Webmaster tools tells me I have duplicate meta descriptions and title tags - what should I do?

This site is hosted by blogger, but it is my own domain that I redirected via Namecheap. The site takes the form of 10 tips, and as such each post has exactly the same title and url apart from the last digit(for example, dog-training-tip-1.html, dog-training-tip-2.html). As a result, in the 'html suggestions' of webmaster tools, it tells me that all 10 meta descriptions and title tags are the same. I assume this is because only one digit separates each post url.

I can alter the titles of each post, but the url stays the same. Is there any way I can alter the urls? Maybe in the html code? Otherwise, I'm going to have to delete the posts and put them up again. My question is - will that hurt my site in terms of ranking? This is a Christmas themed site that I started at the end of September and I was hoping to rank in the top 10 in the next few days/weeks. I don't want to get penalized by Google though. At one point, the site was number 8 in Google, but now it's way back at 180. All help and advice much appreciated