I don't think you are going to get any realistic ideas, as so much is unknown. Such as:
1. Are you prepared to have the laminate flooring lifted to lay pipes underneath? Lifting and relaying would probably require a specialist at extra cost.
2. Which way do the floorboards run, and is there a vent space under the joists beneath the boards?
3. Would you be prepared (and is it feasible, allowing for doorways / other openings) to have the pipework surface mounted?
4. Where is the nearest point where the 22 mm backbone pipework could be tapped into?
5. Can the boiler cope with an additional radiator? (Almost certainly yes).
6. Can a radiator of sufficient capacity to heat the room be fitted where you want it? (Again, almost certainly yes).
I'd suggest you get one or two plumbers, preferably vouched for by friends / family, to give you an estimate. You might get a fixed price quotation after a site visit, but so much will remain unseen until the job starts I for one would only give an estimate and a day rate.