I picked up Portuguese within six months although I had the full combo: Live in Brazil and everything is in Portuguese. Portuguese is way harder than Spanish. I got Spanish down after a couple of weeks, super similar to Portuguese, but easier verbs.
Your best bet is to literally change your daily language to Spanish. Watch everything in Spanish with English subtitles, change your electronics to Spanish, read Spanish books, speak in Spanish and (obviously) study. Should take you less than a year.