Agree with Edward about timing although it can happen much quicker, they only process 50 a day so f you number 51 in the queue, tough, you'll have to come again.
However, if you are reasonably intelligent, you can do it yourself.
If you need to get or renew your residencia, you can download the form off the website for the Ministry of the Interior.
Here's the link : http://www.mir.es/SGACAVT/modelos/extranjeria/modelos_extranje/ex_16.pdf
Fill it in and take 4 passport photos along with your contract of work or Escritura, passport and NIE (plus photocopies of all of the documents) to the Police Station in Las Americas near the bus station.
They can sort it out there for you and it only costs about 6'80.
The actual page with all the info on that tells you what you need etc. is here, as different types of residencias need different supporting documents : http://www.mir.es/SGACAVT/extranje/r...esidencia.html
It's in Spanish though, so you may need to get someone to read through it for you. I have provided a quick translation of some of the page below.
DOCUMENTATION NEEDED - A quick translation!
Three recent passport photos , in color, with a white background, passport sized.
Document of identity or passport, relevant to your nationality, the holder of which has the right of residence. (One must present the original one and a photocopy).
If you have mental health or health problems, you must present certification supporting your state of health.
If you are applying as a relative of a resident, you must present the following documentation in addition to that mentioned above :
The document that accredits your relationship with the resident relative in Spain.
The documentation supporting that your relative resides in Spain. It is also recommended that you also provides a photocopy of the ID, certificate of residence or card of the relative that supports the application in case they moan (It actually says that! )
The visa of residence in the passport, or request of exension of the supporting person, that should to be presented jointly with the residence card request.
Document proves that the applicant lives on the earnings of the relative that supports the application (not applicable for a spouse or for children less than 21 years).
The relatives of workers that had deceased in Spain before they have acquired the right to reside permanently, justification of some of the following circumstances:
Residence in Spain of, no less, two years before the moment of the death.
That the death of the worker happened as a result of industrial accident or professional illness.
That surviving spouse has been a Spanish citizen and has lost their original nationality as a result of the marriage with the worker.