Dell 1535 Internet problems

Thank you for your time.......I have this dell 1535 and do not know what to do to get online wireless. I was told to just use the ones I have and piggyjump them but most have security passwords anyways and one that I did try doing that (netgear) caught me and made up a new one. I also have a dell desktop and on time warner roadrunner and when they installed it they only used one box and the computer is installed to that and there are no other outlets available on the box. I have a seperate d link wired but not sure if I can use it for the laptop? Do I need to go and purchase something so I can use the computer and wanting to use it wirelessly? I hope I have epxlained the situtation not being computer literate and any other questions, please ask and I wil do my best answering. Thanks so much.........