You can significantly increase the shelf life of crushed grain by vacuum packing it (by exactly how much, I'm not sure...I always use mine within a few months). If you don't have the capability to do that, then following the magazine's suggestions for shelf life is probably the thing to do.
If you have a local HBS, they might be able to crush grain for you the day before you brew for a small charge (a few cents a pound). If not, you'll need a grain mill. The cheapest kind is called a Corona mill, and it will probably suit just fine for extract + grain recipes. If you want to get into all grain brewing, I recommend a roller mill like the Crankandstein or MaltMill. If you're handy with metal working, there's a link in my signature about the grain mill I built from scratch.