The change interval for the timing and auxy belts is 90,000 miles or 10 years so you have a wee while yet. If you aren't going to do it yourself (if you've never done it before or don't have the tools/ patience to work in really tight spaces) I'd advise getting a good local mechanic to do it. All in my whole lot came to £240, I sourced the parts myself from OEM but a Gates kit will contain exactly the same bits without the additional Isuzu stamp and will work out a little cheaper. Don't bother with the Honda fixed price nonsense as for the same cost they will only change the timing belt and not bother with the tensioner, idler and bolts.
BTW what you have shown ist the auxilliary belt, the timing belt is under the black plastic covers inboard from that. Don't skimp on that either, on our model it drives either the water or oil pump (can't remember which) rather than the timing belt. If (for whatever reason) you want to remove the A/C there is a shorter auxy belt option as well.
