Since you apparently don't have a sales document that breaks out the sales price by asset group, etc., I would use the method noted by @Critter-3. Drop your assets original price into an excel worksheet, determine the percentage, and let excel determine the sales price allocation. You then enter those amounts into TT.
This could be challenged, may not lead to the best allocation, however, it is all you have at the moment.
*A reminder that posts in a forum such as this do not constitute tax advice.
Also keep in mind the date of replies, as tax law changes.
