Hollowfied

I cannot get my download speed up to where it should be for whatever reason... example.. i should be 100+ kb/sec but it has a hard time going above 30 kb/sec. so my DL time is ridiculous long. Is there any way i can close the download window and open later for continued DLing? Im trying to do a free trial but i closed it once and it reset all the data. and im not up to leaving my comp online for days at a time. Any help would be GREATLY appreciated on this issue.