If you're serious, let's not pussyfoot around. While it is very important to take in more knowledge, make sure you are not making any mistakes at your current level. I understand that all learners make mistakes, but there are lot of of errors in your own writing. Some of them are a result of laziness. You can post texts below for correction. As a professional I assume you don't want to have low standards. http://www.italki.com/notebook

In addition to whatever formal study you are doing, look for ways to expose yourself to the language of your professional field. This is easy on the Internet. With technical material, it may be mostly vocabulary; you may find that grammar is relatively easy because a lot of it is declarative sentences in the present tense. Very seriously, I suggest you read Wikipedia articles in your professional area. They are usually written in pretty good English, and it is an easy way to find technical articles on the precise area that interests you.

Take lessons with a Professional teacher. You will also have to do many hours of self study and practice.