I need to convert half of the kitchen and boiler room into a shower and toilet,how can I and how much will it cost

Not knowing where you live and you skill level I'd siggest getting 3 porfessional bids. Ask the bidder lots of question and maybe you can figure if it really is something you can do or do you need a pro. A bath with a shower needs a 3" drain under the floor which is not there now, what is your floor material and how far to the nearest 3" existing drain?

Like buddy said,get three qouts and also ask if you can help to cut down on labour expense.I don't no your skills but your willing to tackel so you must no a bit.Rule of thumb is the labour cost will be the same as material cost, good luck.