You need to start by getting married, and filing a visa petition on her behalf to show that your marriage is bona fide. Attached to the visa petition should be your marriage certificate, documents which terminated any prior marriages and a document which proves your U.S. citizenship.
Speak with a lawyer to walk through the process and determine if there are any special circumstances to your situation.
You would need to first file an Immigrant Petition for Alien Relative with USCIS here in the US. Notification of approval of this will then be given to the National Visa Center - the unit of the U.S. State Department which centrally handles immigrant paperwork processing for consulates abroad.
The NVC will send you a fee bill for the costs (via e-mail), and once this is paid the materials for processing through the consulate would be submitted. Here is where you would submit an Affidavit of support, with documentation of taxes, income, etc.
Once NVC is satisfied with the documents, and appointment date at the consulate would be scheduled for your wife's interview.
The paperwork is intensive and intricate, and not all of the questions are clearly worded. Speak with an attorney to assess your case and obtain further guidance on the process.
Another option you may wish to consider would be for her to obtain a Fiancee visa and come to the US to get married. You would first file the fiancee petition with the Immigration Service in the US. After that is approved, she will have a visa interview at the US consulate in Colombia. Upon approval of her Fiancee Visa, she can travel to the US. You and she will then need to get married within 90 days, and then she can apply to "adjust" her status in the US and receive her "green card."