No sleep....

I have a 7yr old and a almost 3yr old. We live in a 2 bedroom place, so they have to share a room. Every smurfing night I am constantly up and down every 5mins, coz they just won't go to sleep. Some nights it can seriously take them 3 hours to go to sleep. Iv tried everything. Reading bedtime stories. Half hour of quiet time before bed. Going in at separate times. Talking to them about it. Yelling and screaming and they still carry on. Tonight I even threatened to take their Xmas presents back to the shops, and I get laughed at, then as soon as I walk out, they are at it again. Iv honestly had enough. When iv yelled at them I feel terrible. I lock myself in my room and just cry. I feel like I'm failing as a mum coz I can't get my own kids to sleep.
Anyone have any suggestions?

i wish!! my 2 daughters share a room and it's a nightmare getting them to stay in bed and go to sleep

I also have a 2 bedroom place and knew from past experience my kids would never settle down to sleep at a decent hour if they shared a room. Instead, they each get their own room and I sleep on a futon in the living room. You could also try moving one of the kids bed in your room and have one of them sleep in the room with you instead. I would have probably done that if I had ha a bed already.

See the prob is, I'm currently 37+5 with baby number 3. So we're going to have the baby in with us while its in a bassinet. We have a study area which is just full of crap atm, but we will eventually move our bed into that, and our eldest will have her own room, but the 2 youngest will have to share.....until we find a 4 bedroom place we can afford. Prices in Sydney are freaking ridiculous!!