There is no quick way around this. If you are at the end of your project, footage and graphics are in a HDV sequence, my recommendation is to use Export to Compressor from an unrendered timeline. By doing this your graphics and effects never hit the HDV compression. Do a short trial of a minutes worth so see how you like the results. Try turning on Frame Control and test the higher quality settings vs. the time it will take. This locks up FCP and Compressor for the whole process but for me this is the best way to get around the HDV codeec after the fact.
By Full HD I’m taking you to mean Uncompressed or ProRes but keeping the same framerate, but you may want to be clear.