Even if it's just for the printing side of things, you really should get a decent spec PC.

The printing, viewing, rotating models - not so power hungry, most laptops have sufficient graphics onboard to handle these tasks,
but it's the slicing of the models that takes the CPU power. For you, an I5 laptop, or I3 even, 2gb of RAM and at least 512mb onboard video absolute bare minimum.

On one PC, I have a model that is 81mb and it takes 16 minutes to prepare/slice for printing, it is an 8 core CPU...

The same model on another PC, a standard I5 it can take nearly 25-30 minutes to slice. It all depends on the detail of the model. If you plan on printing simple objects, then don't worry about it - but if you are printing items that require alot of detail, this can take longer to slice for printing and require more processing power.