need help regarding downloading bf3 to origin

i need help regarding downloading games to origin.

I have got legal origin games cd keys i got from donating at humblebundle.com

first off i want to play battlefield 3.

Now, My problem is i have bandwidth restriction at my place so i cant download 18+GB just for bf3 (and not counting another 60+GB of other games that i got from humble bundle) in my pc at my place from origin client.

so i want to use game files downloaded from torrents in my origin client to play games legally with cd keys that i have registered with my origin account. [my friend has unlimited bandwidth and he can download torrents]

my question is:


"how to use game files downloaded from torrents in origin client?" [without crack of-course as i have legal cd keys already registered to my origin account]

i want to know if above mentioned thing is possible and if yes, how?

thank you in advance.

p.s. if this is a wrong section i request admin to direct me to appropriate section thank you.