I think that if you go with the shirt, and tie with no jacket it might just work, however I think that a jacket would be even more appropriate.

I am not sure if you have any tartan shops in your area, if you do there may be a couple of things you can do one would be to rent an Argyle, the other thing is that you might be able to find a used jacket on consignment. I was able to find one like that for $40.00.

You might be able to get your jacket converted but it is this Friday and it's Tuesday already, so if you are going to go that route you should get busy. Please don't just wear the kilt with a normal suit jacket, it just does not look right.