Wanted: Old stuff for first fixed please

ChrisNW Your front rim looks like it's alloy (Mavic?) and as long as the breaking surface is okay, just use that.
Buy a set of track hubs from SJS cycles £40, and one rim (my cheapish rims are Mavic Open sport, SJS have these for around £18).
A reasonable set of spokes will for less than a tenner, plus an appropriate sized spocket for another tenner.

Your existing brakes should be okay if you dismantle and remove the auxillary levers
You should be on the road for less than £80.

yep, perfectly doable, but you'll have to have the tools and skills to build the wheel - which is actually fun to learn (to say i just built another set myself today). or get help from arup on this forum he can build it for you for a very small charge. he could even source the parts and calculate spoke lengths for you in one go to save you all the hassle. could also disassemble that rear wheel and reuse the rim if you really want to keep the cost down.