It's hard to say. If your engine may be on it's way out, I'd say do the engine swap while you have the money to do it (an engine swap with no money is VERY hard to do...). So I would have to go with the engine if I was in your position.
But, if your engine is very reliable and will continue to be, I would get the lift and tires.
Or, you could always do the engine swap and then get a cheap set of tires to go on your existing rims ($200 for a set of decent treaded 30-33's that'll get ya by for a while?) and trim the fenders if you have too much rubbing. and do a homemade leveing kit. I got washers from some place in Tacoma I think, and the 1-3/4", "leveling" kit only costs me 20 bucks (6 washers for each side and I think they were something like $3 a piece).