If you are following the lifestyle then your BP should get to where it needs to be eventually. Check if you are getting enough potassium and magnesium. Fitday is a site everyone recommends so you could pop your food in and have a decent idea on what you nutrients need and get a breakdown of your macronutirent ratios. Too little salt can raise BP in some people too, so make sure whatever salt eating is unrefined and natural like a good quality sea salt.
I don't really like the whole idea that below 120/80 is normal for everyone. It doesn't take into account a lot of variables like age, gender, height, weight etc. Check this out - http://www.bmj.com/cgi/content/extract/326/7399/1104-a I guess they are trying to drug more people. Stress reduction and relaxation can help lower your blood pressure too. So make sure you find time to just chill out.
That said if you are overweight you are likely to have higher blood pressure, so losing weight like you have done already will help.
"My mom made two dishes: Take it or Leave it." -- Stephen Wright, comedian