first of all you need to understand u r very late in your treatment .that is y u have this much of problems in this very early stage of ur life .do not bother about the charges of teeth replacement bt first try to get rid of disease that is spreading in your mouth .
Next Steps
find a good trustworthy doctor get all caries removed first and do good professional cleenup
Health Tips
try to get knowledge about how u can maintain ur teeth and gums healthy and start working on it.