If you can, go to the mall and visit more stores (department stores such as Nordstrom as well as J.Crew, Banana Republic etc.) and try on all the blazers/suit jackets you see. It takes a dozen jackets before I ever find the right one....Blazers come in all different lengths—if it's too short, a blazer can look awful and boxy, but if you find the right one, it will make all the difference. Just because those two pieces are more expensive, they will not necessarily fit you well—although they are still beautiful items! To combat the problem of "boxiness," look for a longer blazer that falls straight, with narrower lapels. Also, a stiffer, heavier fabric will look boxier, since it does not move as well with your body. Lastly, one of the best pieces of advice I ever heard, from a male friend: He bought his suits at Salvation Army, but then had them tailored impeccably, making the suits look rather expensive. So consider that you need to tailor your blazer.
Here's an example of the style of blazer to which I am referring:
http://www.zara.com/us/en/woman/blazers/houndstooth-blazer-c756615p2952506.html (Although I wouldn't recommend the houndstooth for an interview—just a general example of the style itself. Nor do I recommend leather pants.)