You are in the right category and on the best high tech forum.
You wrote that your budget is 1100$, since you wrote the $ sign after the number I assume that you are from a French speaking country. I don't know how far $1,100 will get you were you live.
Here, in North America, $1,100 would get you a top notch machine that would meet all of your needs. Building one, searching for parts compatible with your motherboard, installing an operating system could be challenging. But if you have never built one, it could be troublesome and without warranty.
Considering your needs and funds, I would shop around; look for reputable brands and stay away from lower entrance grades such as Acer. You would also benefit from a free operating system, free support, free upgrades and a warranty.