From the look of the bike, would go with the 'Buy New'' option, the main reason being, that the bike you currently have looks to be way too big for you with the current set up, The lack of seatpost showing & and the length of stem / rise on it both indicate the size is far to big for your needed.

Additionally, the forks look to have worn stanchions from the photos, discs mean new wheels, you will get better value for money on a new bike than trying to upgrade the bike you currently have.

For the shifter indicator, is there really an issue, as you don't get indicators on most shifters from SLX level up now.