I average about $150-170/month Cdn $'s, about the same number of calories you mention. And that's allowing myself "luxuries" like Tropicana orange juice (vs. the frozen concentrate much cheapter) etc. VERY easy to eat healthy and cheap... IF you really know/learn your prices well, use the flyers and coupons, and most importantly stay away from pre-packaged pre-prepared foods! Cookies, frozen meals and pizzas, etc etc... usually not the "healthy" stuff you want anyway... is where your bill starts to skyrocket. Also, don't get into a pattern where "this is what you eat every week" and you just go to the store and fill your basket with the "usual stuff"... regardless of price. There are ALWAYS well-priced fruits, veggies, meats, cereals, etc. if you aren't stuck on eating exactly the same things week after week - buy it when it's in season/on sale, buy something different the next week when something else is cheaper. Variety is healthier anyway. I know other athletes who eat no more than I do, but spend twice as much as I do and don't understand how I keep it so cheap... then I go shopping with them and watch how they shop... and it's easy to understand - they don't even LOOK at the prices.
$40/wk should be no problem if you pay attention, and no need to survive on pasta and oatmeal alone. You might need a bit more at the beginning to get some "staples" (eg. condiments etc. that last a long time).
Just my 2 cents, hope that helps.