Trouble with my staffy cross terrier and my staffy cross Labrador?

need some seriouse help with my dogs,. i have two my first dog iv had from birth and hand reared it all thru the night for weeks because its mum wasent feeding her babys well this dog is my favourite off course becouse i raised her and is the staffy cross terrier ,.. she is 8 month old and think she owns me,.she chews up the carpets and pretty much anythin she can get she wasent so bad but gotten worse, she pees in the house and does poos i always take her to what she has done and tell her and smack her behind or nose then put her out i always know if its her business on the floor when i show them it because who ever done it well put there ears down and avoid smelling it, i have being doing this a few months and still nothing i have found my self getting very agitated every tym the two are fighting or running about,.i cannot walk them anymore because they pull my every were and wont walk nicely , they stop and sniff everything,. the other day my dog i got first the staffy cross terrier got really nasty with my other dod and started fighting really nasty over a peice off pepperami well the cross lab ended up wi i cut from the other dogs tooth and was bleeding i had to tap them both because i wasent sure who started it, just this morning a saw them play fighting and it is the cross terrier who got nasty again only this tym there was no meat just playing around, i have being told its jealousy from the cross terrier because i hav had her from birth, i need some help techniques training methods n so on,. i want to be stern but with out making them scared off me cos they do flinch away wen i get up n tell them off,..... the crosslabrador will cry before going out and willl do her business most tyms in the garden but she eats her poo if im not there to stop her, these dogs are becoming a handfull but i love them to much to get rid off them because it would brake my heart,. im in desperation for help, i have tried a dog trainer it only worked for a few week,. altho it did learn my dogs a few tricks :) pls pls some one help thanx