If you syphilis, you need to be treated by penicillin. You may require a few penicillin treatments by injection if your disease is more advanced. Check on the link below that explains more about the treatment for syphilis.
http://www.nhs.uk/Conditions/Syphilis/Pages/Treatmentpg.aspx
Your sexual partner also needs to be examined and treated too. Do NOT have any sex and avoid skin contact with others so as not to pass on the disease.
I'm not an expert on syphilis, so I don't exactly know. On the American Sexual health associasion website you could ask Dr Hook or Dr Hunter(formerly they did the expert answers on this site). It's a paid service, but they are very good and are really experts in these fields.
Chinese doctors say at least two years or more.If the RPR remains unchanged (1:2) or values continue to fall ,it can be considered a child's problem.
Personally I don't think you need to wait that long, but please check every few month and if it lowers more quickly it looks very good. If it lowers slow, maybe the doctors want to give additional treatment to let it progress more quickly. Is your husband also havinh penicilin for syphilis? Because otherwise you can get reinfected again.