Take painkillers for as long as you need to - don't be a hero! If you need something stronger than paracetomol, ask the doctor for it.
Finish the anti-b's, but if they don't work on the infection, go back to the doctor, or A&E even. Infected wounds can be nasty.
Rest as much as is humanly possible, but with small bursts of light activity in between (I mean light - a short walk is enough!). Try not to bend/lift/contort into awkward positions when getting in and out of bed etc. Don't lift anything heavier than your baby (and even then, proceed wit caution). Do NOT go shopping and carry heavy bags, or lug your buggy into the car boot etc.
Basically, you want to get good quality physical and mental rest and recuperation, but not lie down so much that you seize up and walking becomes difficult.
Press a pillow gently against your scar if you need to cough.
Try to follow all of this until your six week postnatal check-up.
When the scar has dried up and is no longer 'raw', you can use arnica cream to reduce swelling / scarring (seek medical advice before doing this, though).
How are you feeling emotionally? Emergency sectio can leave you in a state of shock, so do take care of yourself, and be honest wiyh your loved ones / health visitor etc if you feel your are struggling at any point.
Oh, and congratulations! 