Don't wish to be the bearer of bad news...
It will be a real squeeze. You'll get the seat in, but might have to get a saw to the legs off your child.
If the seat you refer to is the baby carrier (rearwards facing carry cot thing) you'll have a real nightmare.
We tried, and failed. I was heartbroken at the time, as I was just about to buy a GTV when I found out about the imminent arrival.
I bought a GT pretty much because of it, also the only pushchair that will fit in the boot is a quinny zapp.
The 9months+seat (like we are using now, daughter is 2 and doesn't need a pushchair any more) will just about fit, but you need to move the front seat right forwards and even then the leg room will be a joke.
If you currently have a coupe (I looked at one as an alternative to the GTV) you will have a LOT more room, so see how you get on with that.
My other half had a classic mini when our daughter was born, and she reluctantly had to part with that too.
Worst part about having kids... compromising on your wheels