As a first step, run the inbuilt calibration tools in Windows 7/8 or in OSX
http://www.pcmag.com/article2/0,2817,2414252,00.asp
http://www.computer-darkroom.com/col...olorsync_1.htm
I would be wary of getting a Spyder, if you do, check the Spyder calibration, they have an appalling quality record, We have had as many as 2 out of 3 be out of calibration.
We stopped using them at work and now use the i1, much much much better product.
http://www.xrite.com/product_overview.aspx?ID=1454
If you do get a spyder, have it checked against a known calibrated source.
If you want something cheaper, check out the X-Rite ColorMunki Smile
http://www.imagescience.com.au/produ...nki-Smile.html