Hi,
Firstly, welcome to the forum!!
If you want bars, you'll probably be best getting Renthal ones, there's a UK shop selling them
here (with decent measurements). About the closest to stock is the "Low" ones IIRC (model number 754-01-... then add the letter for the colour you want - 754-01-S actually look better on a 2003 bike than the standard bars IMO!).
As for fitting them, if you're confident with a screwdriver & spanner, it'll take about an hour. Note that the left grip is glued on, and you'll need to remove it to get the clutch lever off easily. Also the stock bar-ends won't fit, so you'll need to replace these.
When fitting, be careful to check lock-lock once switch-gear is on the bars before you tighten up the clamps.