Mahalaxmi and Laxmi are two different manifestations of the Divine Power. Mahalaxmi is the life force of the universe. Laxmi is conventionally the consort of Bhagwan Vishnu.
In the act of creation, Mahalaxmi is the Mistress of the North-East Quadrant. Hence, kings of yore placed temples dedicated to this Devi in the northeastern border of their respective states. Such temples are extant in present day Kathmandu, Lalitpur and Bhaktapur.
नमस्तेऽस्तु महामाये श्रीपीठे सुरपूजिते ।
namaste.astu mahAmAye shrIpIThe surapUjite .
शङ्खचक्रगदाहस्ते महालक्ष्मि नमोऽस्तु ते ॥ १॥
sha~NkhachakragadAhaste mahAlakShmi namo.astu te .. 1..
Complete Stotram: श्रीमहालक्ष्म्याष्टकम्