Different laser platforms and companies have different parameters over what they can and will treat. Prescription is by no means the only factor to consider in ones suitability for treatment. You can have have a small prescription of -1.00 and be unsuitable.

However, from a purely prescriptive point of view I have found the following lasers capable of accurately treating prescriptions as follows:

Allegretto Wavelight : From +8.00 to -16.00, up to -8.00 astigmatism
VISX Star 4 : From +2.00 to -9.00, up to -4.00 astigmaitsm
B&L : I have not worked with, I understand to have slightly better capabilities than the VISX.

Most high street companies will not be looking at treating much more than -9.00 sphere, -3.00 astigmatism or more than +2.50 (if at all).

So yes your prescription could be too high to have laser, however, there are further options including ICL or Phaco IOL treatment depending on your age, suitability etc. Ultimately, until such time as you have been fully consulted, you cannot be given a clear answer.

Visit http://www.lasik-eyes.co.uk, go for a few consultations and you will have a much better idea of what is and isn't possible. (Do yourself a favour and avoid Optical Express, Ultralase and Optimax - high street providers of rubbish).

Cheers
References :
Refractive surgery