Walter Hinteler wrote:.... and I could imagine that you have to get a new passport and not pages added. (This passport contains of 48 pages ...)
The USA govt can add pages to its passports on request when:-
"The visa/stamp pages in your passport are full or close to full (less than two (2) to four (4) blank pages)."
You have to fill out Form DS-4085 and mail it to an address in Philadelphia.
Pitter, you seem to be one of those really annoying people on the web who think that "everybody" is American.
Try typing "add pages to passport" into Google.
You'll see on the State Dept's website that it's about six weeks for routine service or about two weeks for 'expedited' service.
"During busier times, such as the summer travel season, we encourage customers to expedite their applications if traveling in less than 8 weeks."
If you really are from Colombia, maybe you'd better call your government.