Dates And Time Comparisons

got a quick question guys.

if i use this to parse the current date to the right side of the time.
right(getdate(),7) - i'll get something like 7:30AM.

i also have Times stored in a column of a table, but as a string not a date time.
it seems to compare okay, but when the time is say 1:30PM and im comparing it if its greater than or equal to (>=)to 7:30AM - it doesnt return.

i think its ignoring the AM/PM Meridian Values and just comparing the numbers.

is there a conversion i could use to do this?
ive tried a military time conversion i found but it converts to hrs,min,milliseconds.
convert(char(8),(convert(datetime,current_timestam p,113)),114)

if anyone knows a good way to do this - i would appreciate it.

thanks again
rik