Get some ladybugs and put them in with your plant, lady bugs feed on aphids. I had this problem and thats what i did but it was too slow a cure. Look on google, i came across this dish soap rubbing alcohol mixture that you mist the plants with and this worked for me.
Mayb this can help out (nettles or garlic or neem based insecticides... are said to work well against acrids, aphids etc....). See easy recipes section. Lady bugs too if you can get some. Good luck. http://forum.grasscity.com/organic-growing/335656-natural-insecticides-fungicides.html