That is pretty high. I mean not like you will die tomorrow high, but definately should do something about it. A couple years ago I was diagnosed as having high cholesterol and high blood pressure.
My resting blood pressure was 150-170/100-120, and my cholesterol (I forget the exact numbers) was about 270 and 41 or something like that.
I made a lot of important life changes, and although I still don't really exercise I have changed my diet up big time. When I was diagnosed I was 244lbs (I'm 6'0"), now I am down to 190 and I'm hoping to hit 170-175 soon.
Last time i checked my blood pressure it was 128/85, and my last cholesterol test showed my bad at 160 and my good at 90 (I think). Either way my doctor said that things were now just fine and I should live much longer for it.
Looking back it is amazing the crap I would eat. I seriously ate at mcdonalds 3 times a day 2-3 days a week, ate big bags of chips (the 300g bags) every time I watched a movie, and usually followed them up with big bags of skittles, I would always grab those cheap bags of licorice from wal-mart by the dozens, etc. Switching to eating healthy has saved me a ton of money and hopefully given me a few more years to enjoy that money, although I am still at very high risk for heart disease and heart attacks, but that is all my family's fault
I forgot to mention, the first time I was diagnosed with high blood pressure they put me on medication right away (I was 16), and all it did was make me sick to my stomach and EXTREMELY dizzy every time I stood up, I blacked out a few times too, awful stuff really. Needless to say they took me off it after 2 months...
If diet and exercise aren't enough to bring your cholesterol down then you should get on medication for it right away. Although depending on how bad your diet is it could be enough.
Just remember, stay under 15-20g of fat a day, keep trans fats as low as possible (0 is good), every time you eat something fatty or sugary eat something with lots of fiber in it with it (i.e. celery with your supper, carrots with lunch, something like that), and try to keep around 2000 calories per day (less if you want to lose weight).
Another thing that made a big difference for me was to start taking vitamins. Apparently my diet didn't provide me with enough, because about half-way through my diet I started taking vitamins in the morning (1 multi vitamin, 2 calcium, 2 vitamin c, 1 omega 3-6-9) my rate of weight loss doubled and my blood pressure came down significantly.