OP, i have the same laptop and it's not slow imo. For your tasks, it should be more than enough and I don't think your tasks would push the processor enough to create a noticeable difference between the two processors.
The difference between i3 and i5 isn't all that much
http://starredreviews.com/intel-core...fference/1934/
http://www.cpu-world.com/Compare/518..._(PGA988).html