Most business English courses are not at the advanced level because there is such a small market for it. Most English learners fall into one of two groups. One group is the students who major in English but have no real understanding of business. The other group is the students who know a lot about business, but have a very limited English vocabulary. This makes it very challenging for the few hard working students who have mastered both topics to get ahead.
Business is a subject in itself and true business English is a very high level topic that most native speakers are not very well versed in. If you want to learn advanced business English, you must first get your English level to a reasonably high level first. Then you must learn a lot about business and economics in your own language. Without this background knowledge, it will be difficult to learn it in English for the first time.
Once you have mastered basic English, try watching the business news channel. Listen to business English pod casts that teach advanced vocabulary and then watch the news again. You will notice that a few hundred vocabulary terms will be repeated over and over again in the newspaper and on TV. You will be able to participate in advanced business conversations in English. It is important that you write down the terms you learn and make sure you truly understand the concepts instead of only having a loose understanding of what is being talked about. It is also a good idea to speak with successful business people who enjoy talking about business and can use the lingo well.