Screen shot by J Kyrnin
The old content
The best places are in the first paragraph or two and in the headlines (using header tags). I've updated the first paragraph and put the keywords where it made sense in bolded text and headers throughout the page. Don't go overboard - you want the page to be readable and interesting when you're done.
On the other hand, you might be surprised at how much repetition you can get away with. People don't read Web pages, they skim them. So if you repeat the phrase that just means they're more likely to see it, not that they'll notice that you repeat yourself a lot.