It is not an easy question to answer. Whether or not one can make translating a full time job depends on many things. First, of course, it depends on whether one is confident about his/her ability as a translator and the quality of his/her translation. Then it depends also on his ability to market his service. To be able to make translating a full time job one must be sure that the income from this job can be relied on for a living. Otherwise, one will not be able to totally depend on it as a full time job.
How can we change translating from a side income generator to a full-time job? Firstly we have to be sure that our service as a translator is marketable which means that we feel sure that there will be regular demand of our work from the clients. It is not impossible to do if you are serious about making a living by translating. At present there are many publishers which need quality translators to help them translate foreign books into Indonesian or possibly Indonesian books into English. Once you are accepted as a translator for a publisher, it will not be hard for you to find translating job to do. You will be regularly assigned by the publisher to translate foreign books into Indonesian or vice versa. The fee of course depends on the contract between you and the publisher. In addition to working as a translator for a specific publisher, you can also offer your translated work to various publishers which may be interested in publishing your work of translation. It means that you work as an independent translator, you can work for many publishers at the same time. Well, the choice is yours.
I myself have been working as an independent translator for many years now. Although at times I may be bound by a contract with my client but it is not a permanent contract, it is only a temporary contract between me and my client for a certain project of translation. The contract is over when the job is done. The contract is oral contract based on trust. When the job is done, I will be paid accordingly and the contract is over.