Need some advice

Basically, I'm currently studying A2 and want to go to Uni next year, but now I don't think I'll get good enough grades... I'm predicted CDD, which I think I'll get but maybe CDE is more realistic. So, after some research, I've worked out I could do a BTEC at the local college for two years. Only thing about the BTEC is it starts next year now, and it's a 2 year course. I currently work part time, but could easily go full time until next summer for when the BTEC begins.

Questions:

1) Is it worth completing my A-Levels and possibly failing, then going onto BTEC; or quit doing my A-Levels, go full time on my job until next summer?

2) When going through UCAS, would I be able to add my A-Levels with the BTEC, or do they have to be separate things?

Thanks in advance for anyone that replies.