My box has totally gone i think

booked in at renault tommorow and ive not driven her since last sunday. Its been a pain for a while sometimes not going into 2nd. I was driving a bit hard down a country lane, im sure the top end power just wasnt there as usual, tried to select 3rd accelerating from a bend and it just wont go. carefully drove home with no 3rd gear, put my foot down once in 2nd gear and theres some nasty rattling from the gearbox

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Any1 have any idea how much im gonna have to pay (worst case scenario) for a recon box and fit at renault? the engine needs looking at too, keeps stalling on these cold mornings, i have to run it for 10 mins each morning, restarting upto 5 times as the idle drops right down to nothing

its weird, has a mind of its own, revs will drop right down then might sudenly rev to 1500 / 2000 revs then stall :/ ?? I thinjk this is a computer / sensor problem, ive already replaced inlet air temp and water temp sensor but no joy. Mayaswell get ma heater motors fixed too and im sure engine mounts aint 100%, gonna be a dear do me thinks.