My 89 year old mother has a Brother Opus 151 machine; she is too impaired to change machines at this point. She is having difficulty sewing a 1/4 inch seam consistently and we need to buy an attachment. All attachments appear to need a needle that comes in the middle. This machine is offset to the right . Can you tell me how to move the apparatus or recommend an attachment that will work with this machine. Also the manual has been lost. Can you tell me where to get one. Thanks