Joe black said:
Fix budget to $100 - $500 PER Month
$100 = 5-10 hours in the US for an programmer with decent experience. Let's call that 7 hours. You're saying you anticipate having 7-35 hours of work per month, for a site that looks fairly complicated on the server-side and that you want to add unspecified features to. Having added features to a site as part of my day job, I can tell you with certainty that a "minor" feature can easily take ten hours when it just involves a few database calls and tweaks to a couple pages and heavy copy/paste.
I suspect you will blow your budget, or attract a poor programmer. If you don't think a coder is thinking in terms of dollars/hour, you're nuts. I'm telling you it's very unlikely the changes you want will be as simple as you think.