While it is green, keep shocking the pool. A lot of people will shock the pool and then not add any more bleach until the chlorine level drops way down. This won't get rid of algae. You have to sustain the high cl reading to get rid of algae. Try and test at least twice (and three times is better) per day.

To make your test kit be able to test higher until you get a better kit, you can use a dilution method. Take one part pool water, and add an equal part of distilled water. Take some of this and fill your test vial. Then, multiply your test result by 2. If you need to go higher, mix one part pool water and 2 parts distilled water together. Test as normal and then multiply the result by 3. Etc. This dilution method is not as accurate as a better testkit will do, but it will do in a pinch until you get a better kit and will help you figure out how much bleach to add when you test to get back up to shock level.