How do I 'fix' painted brick exterior?

Chances are you will not be able to match the old brick color with new brick,you may have to repaint the entire house for the color to be the same

Go for a Contrast and Clad it.....Better than a bad match........

Color is EASY... just paint it another color, grays are particularly popular right now... and they look good and go will with many other accent and trim colors as well as white (medium gray body, white trim, stained cedar shutters and siding... bright color on the door like turquoise or Plum...NICE!)

For the new construction...Horizontal Cedar siding or ship lap type composite siding, or board and Batten... something larger, flatter with less busy detail that would be a visual, textural relief from the brick..easier construction and cost effective. you could remove the brick in one or more areas... say around the front door, or the other end of the house. and match that area with the new style of siding (there might be a way to go over the brick in one or more areas) Or match the new area with large, simple shutters, stained cedar or painted wood in a style to match the new areas. (I saw this done several times on a show called Zombie House Flipping on FYI network and it made a huge difference in the appearance and curb appeal of the house(s)

Check out several of the DIY and HGTV flipping shows... they are always on a budget and often dealing with modifying or adding on to a brick home... any of the Flip or Flop(s) have all shown this blending of brick and new construction or re-hab where brick has had to be taken off... check it out.