Ladybugs are the natural predators of aphids, and they work well at removing them from your garden. You can buy bags of ladybugs from your local gardening stores or online. Release them at night and they will come back to your garden and continue to remove the aphids for you. The ladybugs should stick around for a while, and this is a good option that doesn't result in any damage to any of the plants in your garden.
Garlic is another natural option that will repel aphids from your garden. Growing garlic in your garden will help to keep them away from the general area, and you can also use garlic, onions, or cloves in a spray that you can use safely on your plants. Grind up your garlic (or onions/cloves) and mix it with water, and strain it to remove the lose garlic particles. Then spray it on your plants, causing those pesky aphids to run right off the plants.