can my internet speed be doubled

i am using a broadband cable connection to connect to the internet, i can add more ip addresses to this account as i already did, i have two ip addresses already one for me and one for my sister, so we can each get full bandwidth, if i added a thirdip address, and used it on my computer with a second nic card, i was wondering if i get double the bandwidth, one computer with 2 nic cards and two different ip addresses, thanks for your time

nicholas hubert