This problem happens when first clutch pistons get sticky, caused by worn out rubber O rings or extremely worn out brake band. On your model it also is due to some sludgy material in the valve body galleries.
You wont be able to find this transmission, but you can surely find people who can repair it. Its not very complicated for an experienced person. The biggest problem with Honda autos is that they do not have a sump to service the filter. To clean it out full tear down is required. Which is 80% of the work of rebuild.