Slow changing into gears seems to be slipping

It takes a while to go through the gears if I put it in second gear it goes from 1st to 2nd ok then I can put it in drive n it will go into 3rd ok but in drive n taking off from the lights ect it revs a fair bit while going slow if I take off real slow its ok still not the best tho ive put a filter kit through it n pan gasket I couldnt put the recommend 7.5 litres in it as it only dropped about 2 n a half so I put that much of fresh tranny fluid back in it I also added a bottle of lucas stop slip in it n its still slipping any ideas on whats going on and how I can fix it please need help asap also can the bands be adjusted?????? Please help