How can I take a GCSE outside of school?

I'm taking GCSE's next year and I really want to take Spanish, but I didn't get it for my options. Is there any way i can take the GCSE outside of school?

Yes, there are private exam centres that allow you to take exams externally. They won't provide tuition though. Alternatively, your school might be able to act as the exam centre if they have the facilities to - ask your exams officer if that's a possibility. However, regardless, you won't be taught so if you're not fluent, you'll need to get tuition privately.

do you know if i can do igcses in jan in uk?

I don't think you can.

really

http://www.edexcel.com/iwantto/Pages/igcse-exam-timetables-uk.aspx

http://www.edexcel.com/iwantto/Documents/7202%20IGCSE%20January%202015%20Timetable%20Final%20v1_DTP.pdf

I found this can't I do the three sciences in Jan, already done Maths+Eng+Stats

I thought all january exams were phased out now, but maybe I'm wrong. Those links certainly do imply that you could sit them in January, so you might be right.

do you know if i can do igcses in jan in uk?

You should be able to, changes affecting gcse don't often affect igcse. I did my igcse maths in January (edexcel) but you have to check if you want to go with the other exam boards as I don't know if they're all keeping Jan exams for igcse. For edexcel they say whether the subject is available for Jan exams in the syllabus so look carefully. Also there may not be as many exam centres that are available for Jan exams, as most just do june.