Do you have a copy of the plan with the original timings / progress etc? If so you can take a copy in excel of your current timings / progress etc so that you have it saved. Then reset the timings in the live version of your plans to the original (now you have the original timings and revised costs). Save and overwrite the baseline for both cost and time. Then reset the timings / progress back to the correct data from your excel save. You will have to go through and reset the summary tasks to Auto Schedule as dropping a copy and paste down the whole column will have set them to Manual schedule.
HTH