I had exactly the same as you. 'Evidence of high risk HPV' does mean that you tested positive for the virus, yes.
Depending on what the consultant can see through the colposcope, they will either treat (most likely with LLETZ) on the day, or take biopsies to determine the true severity level of the changes. Mine did not want to treat on the day as she said it could be CIN1 (mild) or CIN2 (moderate) and with CIN1 they take a watch and see approach because it very often sorts itself out with no help. CIN2 doesnt often do that, hence they treat it. They don't want to give unnecessary treatment though, so we waited for biopsy results.
It's likely they will take some biopsies (I didn't think it hurt at all, some ladies say they feel a little pinch or scratch). If you're lucky it'll come back as CIN1 and they will ask you to come back in a year to see how it looks. If you're not so lucky (like me) it'll be higher than CIN1 and they will call you back for treatment at a later date.
There's no harm in asking the consultant on the day how she/he thinks it looks. I did with mine so it wasnt a huge shock when mine jumped from borderline smear to moderate changes on the biopsy results. My consultant and the nurses who assist her are super-nice and happy to answer any questions. Oh and don't worry too much about the colposcopy, it's not really much different from a smear, just lasts a few minutes longer.
Hope that helps, if you want to ask about anything else feel free