If you want invest the money you made in Thailand the Thailand is not the place to do it. Thailand has such a risky government, bank and visa system right now that you will never know when it will take your money and closes out all foreigners.
You better go with something like Real Estate trust deed investments that will give you 12 % return rate.
The minimum is 25 000 Us Dollar but with that good return rate what do you have to loose? Check the website for more information on how you can invest for a secure future.