There are companies out there that will charge you hefty fees to "repair" your credit. What they don't tell you is that time alone can heal many of the blemishes on your credit report. Late payments age off your credit report. If you are paying your bills on time now and do so consistently, your credit score will improve with each month of on-time payments. Even car repossessions or credit card balance discharges eventually "fall off" your credit report after seven years while bankruptcies are cleared after ten years.
If you have bad credit personal loans will be very expensive—assuming you can even get approved. The best thing you can do is make your current payments on time for at least six months, and better if you can do it for a year, before you apply for any new credit.