Hi Anik Banik if you are just looking for the gene that your 700bp region might fall in I would suggest just using BLAST, if you only want to do it once you can just copy and paste your sequence here: https://blast.ncbi.nlm.nih.gov/Blast.cgi?PROGRAM=blastn&PAGE_TYPE=BlastSearch&LINK_LOC=blasthome
You can try GeneMark-ES, or better, GeneMark-EP+. Also, there’s a script augustify.py in the AUGUSTUS repository on github. (Word of warning: success rate for annotation of foreign sequences with augustify is currently about 50%.)
I don’t recommend the BLAST approach unless you don’t care about the validity of a gene structure or you have sufficient experience to manually curate the gene structure. BLAST tells you s.th. about the locus but does not report valid gene structures including correct splice sites...
Another possiblitiy can be found on http://www.softberry.com/ . On this webpage you find valuable tools for gene prediction (model orgnaisms available). For only one gene you can try annotation of animal or plant genomes (http://www.softberry.com/berry.phtml?topic=index&group=programs&subgroup=gfind). Quit simple the resulting coding sequences can be blasted after ab initio identification.