transmisson leaks

my 904 transmission for small block. started leaking from inside the bell housing and drips out the inspecton plate. then it started slipping in first. now the leak is bad enough to the point where it wont shift unless I fill it again. I stopped driving it till I can do something. I can buy a rebuilt one off ebay for 1250 that come with a stall converter. heres the link. http://www.ebay.com/itm/DODGE-TF904...NES-/161110871697?hash=item2582f4ce91&vxp=mtr
unless u think I should take the one I have and have it rebuilt or is that a better buy? very confused as what to do so i can get my green baby back on the road :(