I like Dianabol but I like Anadrol better. Anadrol is a little more clean and has less water retention. It also is more effective and you get more bang for your buck.
Be careful with the stimulant based supplements. They will give you a buzz and then you'll crash during your workout. This is why it's important to use something that's very clean.
You should also be doing things like lunges, especially holding some dumbbells. Those will actually help your squats improve. And also leg extensions are a good idea.